May 20th, 2018

Suppressors — Why You Still Need Hearing Protection

suppressor silencer moderator facts fiction sound levels noise decibles dB
Silencer-equipped AR photo courtesy The Silencer Shop.

OK, you’ve paid the tax stamp and acquired your new suppressor (aka “silencer” or “moderator”). Do you still need to wear earplugs or muffs? Absolutely. Even with that expensive new “can”, your rifle could be generating over 140 decibels (dB) of noise — about the same as as an unmuffled 9mm pistol shot. That’s loud enough to create permanent hearing loss with repeated exposure.

Firearms Are Loud: 140 dB to 175 dB

Audiology group ASHA explains: “Exposure to noise greater than 140 dB can permanently damage hearing. Almost all firearms create noise that is over the 140-dB level. A small .22-caliber rifle can produce noise around 140 dB, while big-bore rifles and pistols can produce sound over 175 dB. Firing guns in a place where sounds can reverberate, or bounce off walls and other structures, can make noises louder and increase the risk of hearing loss. Also, adding muzzle brakes or other modifications can make the firearm louder. People who do not wear hearing protection while shooting can suffer a severe hearing loss with as little as one shot[.] Audiologists see this often, especially during hunting season when hunters and bystanders may be exposed to rapid fire from big-bore rifles, shotguns, or pistols.” Source: ASHA, Recreational Firearm Noise Exposure.

suppressor silencer moderator facts fiction sound levels noise decibles dB

Suppressors, On Average, Reduce Noise Levels about 30 Decibels
In an article for Ammoland, gunwriter Sam Hoober says that you can expect about 30 decibels (dB) of noise reduction from the average suppressor: “Looking at a few different products, SilencerCo attests their suppressors reduce the sound pressure of a 9mm gunshot to anywhere from 125.7 dB to 131.5 dB, depending on the model. Advanced Armament Co, another popular supplier, attests a 23 dB to 33 dB reduction or down to 127 dB. Liberty Suppressors, another manufacturer, attests a reduction of 24 dB to 38 dB, depending on model and other factors. In short, we can presume something on the order of 30 dB of attenuation as an average.”

Using that 30 dB number you can quickly discern that you’ll still need hearing protection — good hearing protection — when shooting any suppressed firearm (even a .22 LR). “Spikes of 130 dB and more can result in permanent hearing damage instantly”. Source: NRA Blog.

The Myth of the “Quiet” .22 LR
The NRA Blog notes that “many rimfire shooters, particularly those using the beloved .22 Long Rifle cartridge, argue that the small .22 LR caliber doesn’t produce enough sound to damage your hearing”. So, is that really true. or is it a myth?

In fact, a .22 LR can be much louder than you think — a .22 LR pistol can produce sound levels of 134 dB. That’s well above the normal human pain threshhold.

Sound Levels for Common Noises:

9mm Luger pistol: 160 dB

Jet aircraft engine (near): 140 dB

.22 LR pistol: 134 dB

Normal human pain threshold: 120 dB

Noisy Nightclub: 110 db

Riding Motorcycle at 65 mph: 103 db

Power Lawnmower: 95 dB

Hearing damage possible: 85 dB (sustained for 8+ hours)

Ringing Telephone: 80 dB

Normal conversation: 60 dB


The Risk of Hearing Loss
Hearing loss can be progressive and irreversible. If you are a shooter, this is serious business. As the NRA Blog cautions: “You may not even realize you’re harming your hearing. Hearing loss occurs gradually, and can go effectively unnoticed until symptoms become severe. By then, the damage is done.”

Nobody wants to go deaf. But we often see shooters without effective hearing protection when they are walking around a few yards behind the firing line. That’s bad — even if you are away from the firing line, gunshot noises can damage your hearing. You MUST use effective hearing protection every time you go to the range. Good foam earplugs costs mere pennies but they can prevent deafness in your later years. Many folks also wear muffs over plugs.

Permalink Hunting/Varminting, Tech Tip 2 Comments »
May 19th, 2018

How to Zero A Hunting Rifle in Four Shots

hunting zero zeroing sight-in easy NSSF boresighting
Photo courtesy Vortex Optics.

Here’s a simple procedure that lets you get a solid zero for a hunting rifle in just four shots. Of course you probably want to fire a few more rounds to confirm your zero before you head off to your hunting grounds, but this will let you get on-target with a minimum amount of time and ammo expended. (This assumes your scope is securely mounted, and the bases are not drastically out of alignment.)

QUICK-TIP: The Key to this procedure is Dialing to Shot One Point of Impact (POI). Re-aim at center of target after SHOT ONE. Then with the rifle motionless, use the turrets to put the middle of the cross-hair on the first shot location.

1. First, remove the bolt and boresight the rifle. Adjust the position of the rifle so that, looking through the bore, you can see the center of the target with your eyes. Secure the rifle in the rests to maintain its position as boresighted. Then, without moving the rifle, center the reticle. That should get you on paper. With the rifle solidly secured in front and rear rests or sandbags, aim at the center of a target placed at your zeroing distance (50 or 100 yards). Confirm there are no obstructions in the barrel! Then load and fire SHOT ONE. Then, return the gun to the exact position it was when you pulled the trigger, with the cross-hair centered on the target as before.

2. Locate, in the scope, where your first bullet landed on the target. Now, while you grip the rifle firmly so it doesn’t move, have a friend adjust the turrets on your scope. While you look through the scope, have your friend turn the windage and elevation turrets until the cross-hairs, as viewed through the scope, bisect the first bullet hole on the target. In other words, use the turrets to move the center of the reticle to the actual position of shot number one. IMPORTANT: Dial the crosshairs to the hole — don’t move the rifle.

Watch NSSF Zeroing Video showing method of moving reticle to Shot 1 Point of Impact.

3. After you’ve adjusted the turrets, now re-aim the rifle so the cross-hairs are, once again, positioned on the target center. Keep the rifle firmly supported by your rest or sandbag. Take the SECOND SHOT. You should find that the bullet now strikes in the center of the target.

3-Shot Zero

4. Take a THIRD SHOT with the cross-hairs aligned in the center of the target to confirm your zero. Make minor modifications to the windage and elevation as necessary.

5. Finally, shoot the rifle from a field rest (shooting sticks, bipod, or rucksack) as you would use when actually hunting. Confirm, with SHOT FOUR, that your zero is unchanged. You may need to make slight adjustments. Some rifles, particularly those with flexy fore-arms, exhibit a different POI (point of impact) when fired from a bipod or ruck vs. a sandbag rest.

If you recently cleaned your rifle, you may want to fire two or three fouling shots before you start this procedure. But keep in mind that you want to duplicate the typical cold bore conditions that you’ll experience during the hunt. If you set your zero after three fouling shots, then make sure the bore is in a similar condition when you actually go out hunting.

Permalink Optics, Shooting Skills, Tech Tip 2 Comments »
May 18th, 2018

Flip Your Target Colors for Better Long-Range Viewing

Negative target center reverse color image

At long range, small bullet holes are much easier to see “in the white” than in the black center of the normal High Power target. When you’re practicing at long range using a scoped rifle, one way to enhance your ability to see your bullet holes is to print a “negative” version of the regulation bullseye target so that your black center is now white.

How do you create a “negative” of a target image? Many image programs, including the FREE Irfanview software, have a “Negative” function in the pull-down menu. If you don’t see a “Negative” menu option in your program, look for a “substitute colors” option. Many printers also have a “reverse colors” function. If you can’t find a solution with your computer or printer, just take a normal bullseye target to a copy shop, and the staff can easily print you a set of targets with white centers in black fields.

Pentax PF-80 ED scopeForum member Watercam has a Pentax PF-80ED spotting scope that allows him to see 6mm bullet holes in the white at 600 yards. However, 6mm holes in the black are only visible out to 400 yards or so. Accordingly, Watercam uses a modified “reversed” black-to-white target for 600-yard practice. Watercam explains: “[Using the Pentax] With my 6mm and limited mirage I see defined, 6mm holes in the white out to 600. In the black, however, I can see bullets holes at about 400. I now use reverse-color targets for training without a pit partner at the 600-yard line.”

The Hi-Viz Solution — Day-Glo Pasters
If you’re not concerned with official scoring rings, you can use an all-white target with a bright, fluorescent target dot in the middle. A 2″- or 3″-diameter stick-on target dot is highly visible at 600 yards. Birchwood Casey Target Spots® assortment #33928-TSA offers neon orange target dots in 1″, 2″, and 3″ diameters.

Easel Pad flip chart target paper

TARGET TIP — Use Chart Paper
For practice backers for the Day-GLo pasters at long distance, use Flip Chart Paper (aka Easel Pads) marked with graph lines at 1″ intervals. Available either regular or self-stick, one sheet can hold 4-8 pasters and the white paper allows for easy spotting of the holes and quick estimation of group size. Get Flip Chart Paper at Amazon.com, Staples, or Office Depot.

Brits Use White-Field Target for F-Class
In the UK, some ranges are now using a “reverse-style” target with a mostly white area. Laurie Holland says this allows shooters to see shots much more easily. Laurie reports: “Here’s a photo of the 500/600 yard F-Class match target we use in PSSA comps at Diggle Ranges with club members Chris Hull (L) and Terry Mann (R). We now use this target form at all ranges up to 1K for F-Class, and, yes you can often see your hits at 600 yards on the target before the markers pull it. Regards from England — Laurie”.

Permalink Competition, Tech Tip 2 Comments »
May 17th, 2018

Powder Temp Stability — IMR Enduron vs. H4350 and Varget

powder gunpowder temperature sensivity temp stability Hodgdon Extreme Varget H4350 IMR Enduron 4451 4166

A couple seasons back, PrecisionRifleBlog.com (PRB) published a significant field test of powder temperature stability. The test was designed to quantify the temperature stability of Hodgdon H4350 and Varget powders compared to IMR’s Enduron line of powders, specifically IMR 4166 and 4451. The results were very interesting, to say the least…

Hodgdon Extreme Series powders have attracted quite a fan base, with over 90% of the top shooters in the Precision Rifle Series choosing to run one of those powders. IMR offers a modern line of powders “with Enduron Technology” — which is also marketed to have “extreme temperature stability”. Sounds familiar! These new powders should compete directly with the Hodgdon Extreme Series, which gives shooters more temp-stable powder options to consider.

CLICK HERE to Read Full Powder Temperature Stability Test on Precision RifleBlog.com.

The top shooters in the PRS and veteran long-range shooters in other disciplines have learned to value a temperature-stable powder. That’s because a change in temperature can affect the trajectory or “flight path” of the bullet in two well-known ways:

1. Assuming all other environmental conditions remain the same, an increase in air temperature will cause a flatter trajectory due to a lower air density (easier for the bullet to cut through the air).

2. The same increase in temperature also causes the nitrocellulose-based powder inside the cartridge to burn at a higher rate, producing approximately four times the Point of Impact (POI) shift than just air temperature alone. (SEE: Temperature Effects On Zero on KestrelMeters.com.)

“The initial heat condition of your powder will affect the burn rate,” Bryan Litz explained at a recent Applied Ballistics Seminar. That means swings in ambient outside temperature can affect your internal ballistics, which will directly affect your muzzle velocity, which will change your bullet’s trajectory. Some powders are more affected by changes in temperature than others. So if your goal is first-shot hits and you may shoot in a variety of conditions — you should care about temperature stable powders.

The folks at PrecisionRifleBlog.com meticulously loaded 6.5×47 Lapua ammo with each powder using some of the best equipment available. This included the top-of-the-line Prometheus Gen II Powder Scale, which is capable of loading to the nearest kernel of powder. This ensured the powder charges were identical for each round of ammo. PRB’s testers explain the full set of equipment and steps in their loading process in the Full Test Report.

Magnetospeeed LabRadar chronograph chrono powder gunpowder temperature sensivity temp stability Hodgdon Extreme Varget H4350 IMR Enduron 4451 4166

Once they had a couple dozen rounds loaded with each powder, they went and shot them with each powder at 25° F, 65° F, and 140° F. The muzzle velocity of each shot was recorded using BOTH a LabRadar Doppler Radar and a MagnetoSpeed Chronograph. That provided two sets of velocity numbers. When placed and configured optimally, the LabRadar can measure muzzle velocity with +/- 0.1% accuracy, according to the manufacturer.

Here are the results from the PRB Powder Temp Stability Tests:

Magnetospeeed LabRadar chronograph chrono powder gunpowder temperature sensivity temp stability Hodgdon Extreme Varget H4350 IMR Enduron 4451 4166

You can see Hodgdon H4350 had the least variance in muzzle velocity, with just 25 fps over the 115° swing in temperature! That is very, very low. Hodgdon Varget was the second least temperature sensitive powder in this test, with 46 fps of variance in muzzle velocity between temperatures of 25° F and 140° F. IMR 4166 performed very similar to Varget, and proved to be fairly insensitive to large swings in temperature. IMR 4451 had the largest swing in muzzle velocity of the powders tested, but keep in mind just 68 fps over 115° F swing is still a good performance.

Most powders aren’t specially formulated to be temperature stable. So they would likely show much larger swings than what these four top-performing powders showed. However, Alliant’s relatively new Reloder 16 is an extremely temp-stable powder, with a burn rate that is a close match to H4350. Many F-Open competitors are now using Reloder 16 with considerable success.

PRB’s test team also noticed other interesting trends in the data. For example, variation in velocity does NOT appear to be linear across the full range of temperatures. By that, they mean the change per degree from 20° to 65° might be smaller or larger than the change per degree from 65° to 140°.

PRB’s testers talk about those things, provide a few other insightful views of the data, and discuss tools that can help you manage temp/muzzle velocity in the field in their full post. You can find that here: http://precisionrifleblog.com/2016/06/19/powder-temp-stability-hodgdon-extreme-vs-imr-enduron/

Permalink News, Reloading, Tech Tip No Comments »
May 15th, 2018

Monitor Barrel Heat with Handy Temp Strips

Barrel Heat Temp Temperature gauge strip McMaster Carr

You never want your barrel to get too hot. Accuracy suffers when barrels over-heat, and excessive heat is not good for barrel life. So how do you monitor your barrel’s temperature? You can check if the barrel is “warm to the touch” — but that method is not particularly precise. There is a better way — using temperature-sensitive strips. McMaster.com (an industrial supply house) offers stick-on temp strips with values from 86° F to 140° F. A pack of ten (10) of these strips (item 59535K13) costs $12.16 — so figure it’ll cost you about $1.20 per barrel for strips. That’s cheap insurance for your precious barrels. For best barrel life, try to stay under 120 degrees F.

Barrel Heat Temp Temperature gauge strip McMaster Carr

Forum member Nomad47 says: “I have temperature strips (bought at McMaster-Carr) on all my barrels. I try not to shoot when the barrel gets to 122 degrees or higher[.]” Here are photos of the McMaster-Carr temp strips on Nomad47’s customized Savage.

Barrel Heat Temp Temperature gauge strip McMaster Carr

Bad things can happen if your barrel gets too hot. First, with some barrels, the point of impact (POI) will shift or “walk” as the barrel heats up excessively. Second, even if the POI doesn’t change, the groups can open up dramatically when the barrel gets too hot. Third, if the barrel is very hot, the chamber will transfer heat to your loaded cartridge, which can lead to pressure issues. Finally, there’s considerable evidence that hot barrels wear out faster. This is a very real concern, particularly for varmint shooters who may shoot hundreds of rounds in a day. For this reason, many varminters switch among various guns, never letting a particular barrel get too hot.

Neconos.com offers Bar-L Temp Strips that visually display heat readings from 86 to 140 degrees. Think of these strips as compact, unbreakable thermometers. With adhesive backing, they can also be used to monitor barrel heating. Put a strip on the side of the barrel and the barrel’s temp will be indicated by a stripe that changes from black to green. There is also a “general purpose” strip that reads to 196 degrees (bottom row). The Benchrest strip (86F to 140F) is in the middle. Bar-L temp strips cost $9.00, or $25.00 for a 3-pack.

Permalink Gear Review, Tech Tip 3 Comments »
May 13th, 2018

Cartridge Headspace — Understanding the Basics

Brownells Headspace Gauge cutaway chamber drawing SAAMI ANSI

Do you know what the inside of a rifle chamber (and throat zone) really looks like? Do you understand the concept of headspace and why it’s important? If not, you should read the Brownells GunTech article Gauging Success – Minimum Headspace and Maximum COL. This article explains the basics of headspace and shows how to measure headspace (and length to lands) in your barrels with precision. The article also explains how to adjust your full-length sizing dies to “bump the shoulder” as needed.

Why is headspace important? The article explains: “Controlling headspace and setting proper C.O.L. also represent improved safety and reduced cost of handloading. Excessive headspace can cause case head separation and gases in excess of 60,000 PSI escaping from a rifle’s chamber. Too little headspace can result in a chamber forced bullet crimp and a bullet that becomes an obstruction more than a properly secured projectile. Excessive C.O.L. can result in a rifling-bound bullet, a condition that could result in spikes of excessive pressure.” [Editor’s NOTE: It is common for competitive benchrest shooters to seat bullets into the rifling. This can be done safely if you reduce your loads accordingly. With some bullets we often see best accuracy .010″ (or more) into the lands. However, this can generate more pressure than the same bullet seated .010″ away from initial lands contact. As with all reloading, start low and work up gradually.]

Brownells Headspace Gauge cutaway chamber drawing SAAMI ANSI

How is headspace specified? Most cartridges used within the United States are defined within ANSI/SAAMI Z299.3-4. Brownells explains: “In the case of the .243 Winchester, as an example, there are pressure specifications, cartridge drawings and, as pictured above, chamber drawings. Armed with a chamber drawing, each manufacturer producing a firearm for the .243 Winchester knows the proper standard dimension to cut chambers and set headspace. Notice there are two headspace reference dimensions for the chamber. The upper is a place in the chamber where the shoulder is .400″ in diameter; the “datum” or “basic” line. The lower is the 1.630″~1.640″ minimum – maximum dimension from the breech face (bolt face) to that point in the chamber that measures .400″.”

The actual headspace of any firearm is the distance from the breech face to the point in the chamber that is intended to prevent forward motion of a cartridge.

Permalink Gunsmithing, Tech Tip 3 Comments »
May 12th, 2018

Six Tips for Better Results at Local Fun Shooting Matches

tip advice training prep club varmint groundhog match

Every summer weekend, there are probably 400 or more club “fun matches” conducted around the country. One of the good things about these club shoots is that you don’t have to spend a fortune on equipment to have fun. But we’ve seen that many club shooters handicap themselves with a few common equipment oversights or lack of attention to detail while reloading. Here are SIX TIPS that can help you avoid these common mistakes, and build more accurate ammo for your club matches.

Benchrest rear bag1. Align Front Rest and Rear Bags. We see many shooters whose rear bag is angled left or right relative to the bore axis. This can happen when you rush your set-up. But even if you set the gun up carefully, the rear bag can twist due to recoil or the way your arm contacts the bag. After every shot, make sure your rear bag is aligned properly (this is especially important for bag squeezers who may actually pull the bag out of alignment as they squeeze).

Forum member ArtB adds: “To align my front rest and rear bag with the target, I use an old golf club shaft. I run it from my front rest stop through a line that crosses over my speed screw and into the slot between the two ears. I stand behind that set-up and make sure I see a straight line pointing at the target. I also tape a spot on the  golf shaft that indicates how far the back end of the rear bag should be placed from the front rest stop. If you don’t have a golf shaft, use a wood dowel.

2. Avoid Contact Interference. We see three common kinds of contact or mechanical interference that can really hurt accuracy. First, if your stock has front and/or rear sling swivels make sure these do NOT contact the front or rear bags at any point of the gun’s travel. When a sling swivel digs into the front bag that can cause a shot to pop high or low. To avoid this, reposition the rifle so the swivels don’t contact the bags or simply remove the swivels before your match. Second, watch out for the rear of the stock grip area. Make sure this is not resting on the bag as you fire and that it can’t come back to contact the bag during recoil. That lip or edge at the bottom of the grip can cause problems when it contacts the rear bag. Third, watch out for the stud or arm on the front rest that limits forward stock travel. With some rests this is high enough that it can actually contact the barrel. We encountered one shooter recently who was complaining about “vertical flyers” during his match. It turns out his barrel was actually hitting the front stop! With most front rests you can either lower the stop or twist the arm to the left or right so it won’t contact the barrel.

3. Weigh Your Charges — Every One. This may sound obvious, but many folks still rely on a powder measure. Yes we know that most short-range BR shooters throw their charges without weighing, but if you’re going to pre-load for a club match there is no reason NOT to weigh your charges. You may be surprised at how inconsistent your powder measure actually is. One of our testers was recently throwing H4198 charges from a Harrell’s measure for his 30BR. Each charge was then weighed twice with a Denver Instrument lab scale. Our tester found that thrown charges varied by up to 0.7 grains! And that’s with a premium measure.

4. Measure Your Loaded Ammo — After Bullet Seating. Even if you’ve checked your brass and bullets prior to assembling your ammo, we recommend that you weigh your loaded rounds and measure them from base of case to bullet ogive using a comparator. If you find a round that is “way off” in weight or more than .005″ off your intended base to ogive length, set it aside and use that round for a fouler. (Note: if the weight is off by more than 6 or 7 grains you may want to disassemble the round and check your powder charge.) With premium, pre-sorted bullets, we’ve found that we can keep 95% of loaded rounds within a range of .002″, measuring from base (of case) to ogive. Now, with some lots of bullets, you just can’t keep things within .002″, but you should still measure each loaded match round to ensure you don’t have some cases that are way too short or way too long.

Scope Ring5. Check Your Fasteners. Before a match you need to double-check your scope rings or iron sight mounts to ensure everything is tight. Likewise, you should check the tension on the screws/bolts that hold the action in place. Even on a low-recoiling rimfire rifle, action screws or scope rings can come loose during normal firing.

6. Make a Checklist and Pack the Night Before. Ever drive 50 miles to a match then discover you have the wrong ammo or that you forgot your bolt? Well, mistakes like that happen to the best of us. You can avoid these oversights (and reduce stress at matches) by making a checklist of all the stuff you need. Organize your firearms, range kit, ammo box, and shooting accessories the night before the match. And, like a good Boy Scout, “be prepared”. Bring a jacket and hat if it might be cold. If you have windflags, bring them (even if you’re not sure the rules allow them). Bring spare batteries, and it’s wise to bring a spare rifle and ammo for it. If you have just one gun, a simple mechanical breakdown (such as a broken firing pin) can ruin your whole weekend.

Permalink Competition, Tech Tip No Comments »
May 8th, 2018

New Mobile Apps for LabRadar to Be Released Soon

LabRadar chronograph doppler radar chrono mobile app iOS iphone smartphone android phone

LabRadar owners can celebrate. New mobile-friendly control software is coming soon. Gunsmith and Benchrest Hall of Famer Thomas “Speedy” Gonzalez had some interesting news from the NRA Show in Dallas. He learned that the creators of the LabRadar chronograph systems will soon offer Mobile Apps that can run on your iOS or Android smartphone or tablet. This new software will make it much easier to control the LabRadar, and offer enhanced data editing functionality.

New LabRadar iOS and Android Mobile Apps Coming Soon…

LabRadar chronograph doppler radar chrono mobile app iOS iphone smartphone android phoneSpeedy says: “I just got back from the NRA show in Dallas, Texas. The coolest thing I personally saw at the show was at the LabRadar booth. They had the Beta versions of their new LabRadar Apps for the iPhone and Android phones. These Apps let you control all LabRadar functions from your phone as well as your tablet via Bluetooth connection. The new Apps will also allow the LabRadar owner to store and edit his or her data from a much larger and user friendly screen.”

That’s good news. We particularly like the ability to edit LabRadar data on a tablet. Speedy added: “This is going to revolutionize this great product and make it [much more] user-friendly.”

The new LabRadar Mobile Apps will be available free for LabRadar owners. If you own a LabRadar, be sure to register your LabRadar on the LabRadar Website. That will ensure you are notified via email as soon as the software is available. To register, look for the text link at the top right of the LabRadar homepage. It says “Register your LabRadar “. Click the link then fill out the data form.

LabRadar chronograph doppler radar chrono mobile app iOS iphone smartphone android phone

Permalink New Product, Tech Tip No Comments »
May 7th, 2018

Recoil Comparison — .223 Rem vs. 6mmBR vs. .308 Win

6mmBR NormaMany visitors to the site ask us, “I’ve got a .223 and .308. What will a 6mmBR Norma (6BR) give me that I’m not getting already?” Well first you may well average somewhat smaller groups than your current .223 or .308 rifle (assuming the 6BR has a quality barrel and trigger). A good .308 Winchester can be superbly accurate, no question about that, but the lesser recoil of the 6BR works in the shooter’s favor over a long string of fire. Even with a Rem 700 or Savage action factory action, a 6BR with a benchrest stock, premium barrel, and a high-quality chambering job should deliver 5-shot groups in the high twos to mid-threes, provided you do your job. We have one 6BR rifle that shoots Lapua factory-loaded 6BR ammunition in the low twos and high ones. That’s exceptional, we admit, but it still shows how the 6BR is an inherently accurate cartridge, even with factory loads.

Compared to a .223, the 6BR offers a better selection of high-BC projectiles and small-maker match projectiles (such as Bart Sauter’s “Hammer” and the Vapor Trail line). The 6BR will also deliver considerably more power on the target. Compared to the .308 shooting 168gr MatchKings, a 6BR shooting 105-107gr bullets offers better ballistics all the way out to 1000 yards. (The story changes with .308s with very long barrels pushing the 180-210 grain projectiles). Plus, for most people, the 6BR is just easier to shoot than a .308. Recoil is less than half of the .308 Win cartridge. Both the .308 and 6BR chamberings offer good barrel life, but the 6BR uses 15-18 grains less powder, saving you money. Here’s how the 6BR stacks up vs. a number of popular calibers:

Permalink Bullets, Brass, Ammo, Tech Tip 1 Comment »
May 6th, 2018

Take Better Match and Gun Range Photos with Fill Flash

camera daylight fill flash shootingWe know you guys like taking photos of your rifles at the range. And, if you’re selling a rifle, scope, front rest, or rear bag, you need good photos to post in our Forum classifieds. Here’s a basic photography tip that can help you produce dramatically better photos. Use your camera’s ability to add “fill flash” even in daylight.

There’s plenty of light on a bright day. But bright light also means strong shadows. The shadows can leave parts of your subject literally in the dark. Daylight flash will help fill in those dark spots. In addition, if you are on a covered firing area, and want to include the range in your photo, you can benefit from using flash. This will prevent the foreground subject from being too dark while the downrange background is much too bright.

Photo without Flash

The photo above was taken without flash. As you can see, the rifle is too dark so details are lost. At the same time, the background (downrange) is over-exposed and washed out. The second photo below is taken with daylight flash. The difference is dramatic. Now you can see details of the rifle, while the background is exposed properly. Note how much easier it is to see the the targets downrange and the colors of the front rest. NOTE: these two photos were taken at the same time — just seconds apart.

Photo with Daylight “Fill-Flash”

Be sure to click on the larger versions of each photo.

How to Activate Daylight Flash
Most digital cameras have daylight flash capability. Some cameras have a separate setting for “auto fill flash”. On other cameras, you’ll have to set the camera to aperture priority and stop down the aperture to force the flash to fire. Read your camera’s manual. On many Canons, a menu that lets you set the “flash output”. For “fill flash” we like to set the flash at 30% to 50% output. This fills in the shadows sufficiently without “killing contrast” or creating too much reflection on shiny metal. Below is a photo taken with 30% flash output. Note the rich colors and how the exposure is balanced between foreground and background. Without flash the sky and target area would be “washed out”.


Here’s another tip for Canon owners. If you like deep, rich colors, use the “Vivid” setting in the effects menu. This punches up saturation and contrast.

Permalink - Articles, Tech Tip 1 Comment »
April 29th, 2018

Vihtavuori Explains Powder Grain Shapes

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

POWDER GRAIN SHAPES — What You Need to Know

The shape of powder grains has a profound effect on the performance of the powder charge, as it concerns both pressure and velocity. There are multiple powder shapes including flake, ball, and extruded or “stick” (both solid and perforated).

All Vihtavuori reloading powders are of the cylindrical, single-perforated extruded stick type. The differences in burning rate between the powders depend on the size of the grain, the wall thickness of the cylinder, the surface coating and the composition. Cylindrical extruded powders can also have multi-perforated grains. The most common types are the 7- and 19-perforated varieties. A multi-perforated powder grain is naturally of a much larger size than one with a single perforation, and is typically used for large caliber ammunition.

Other types of powder grain shapes include sphere or ball, and flake. The ball grains are typically used in automatic firearms but also in rifles and handguns. The ball grain is less costly to produce, as it is not pressed into shape like cylindrical grains. Flake shaped grains are typically used in shotgun loadings.

Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders

Web thickness in gunpowder terminology means the minimum distance that the combustion zones can travel within the powder grain without encountering each other. In spherical powders, this distance is the diameter of the “ball”; in flake powder it is the thickness of the flake; and in multi-perforated extruded powders it is the minimum distance (i.e. wall thickness) between the perforations.

The burning rate of powder composed of grains without any perforations or surface treatment is related to the surface area of the grain available for burning at any given pressure level. The change in the surface area that is burning during combustion is described by a so-called form function. If the surface area increases, the form function does likewise and its behavior is termed progressive. If the form function decreases, its behavior is said to be degressive. If the flame area remains constant throughout the combustion process, we describe it as “neutral” behavior.

The cylindrical, perforated powders are progressive; the burning rate increases as the surface area increases, and the pressure builds up slower, increasing until it reaches its peak and then collapses. Flake and ball grains are degressive; the total powder surface area and pressure are at their peak at ignition, decreasing as the combustion progresses.

So how does the shape affect pressure and muzzle velocity? In general, it can be said that powder that burns progressively achieves a desired muzzle velocity at lower maximum pressure than a powder that burns neutrally, not to mention a degressive powder. As grain size increases, the maximum pressure moves towards the muzzle, also increasing muzzle blast. Muzzle velocity and pressure can be adjusted by means of the amount of powder or loading density, i.e. the relationship between the powder mass and the volume available to it. As the loading density increases, maximum pressure grows.

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Vihtavuori loading propellant reloading powder N133 N150 N140 N550 ball flake stick extruded perforated powders


This article originally appeared on the Vihtavuori Website.

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
April 27th, 2018

Case-Trimming 101: Tips from PMA Tool

Wilson Micrometer Case Trimmer

The folks at PMA Tool, makers of arbor presses, neck-turning tools, and other case-prep tools, offered some good advice about case trimming on the PMA Tool Website. Here we reprint a PMA article that explains case trimming basics and helps you choose the right case-trimming tool for your needs.

Case Trimming Basics
Trimming the cartridge case to the proper length is a crucial step in case preparation that should not be overlooked or underestimated. The cartridge case or the rifle can be damaged, or even worse you get badly injured. In most instances cases should be trimmed after firing and sizing. Trimming new brass is necessary for a lot of wildcats and can be beneficial in some instances, but by and large, trimming new brass is not necessary for most situations (unless you are neck-turning). Cases should be trimmed after you have sized the case, because the expander ball on the decapping pin can (and will) stretch the neck. Those of us who neck size should get into the habit of trimming after sizing as well. This is a good rule of thumb to go by, and hopefully it will keep you safe during the reloading and shooting process.

Forster Case Trimmer

There are so many case trimmers out there that work, deciding which one is right for you can be confusing. Even though I have trimmed thousands of cases, using about every method possible, I can’t answer the question of what case trimmer is right for you because of all the variables that may be involved. I can, however shed some light on the subject.

The two most popular designs of trimmers either index (1) off the base or the head of the case, (2) off the shoulder or datum line of the case. There are pros and cons to each and it all depends on what you are willing to live with.

Indexing off the Base (Case Head)
Let’s talk about the first one I have listed, indexing off the base, or the head of the case. The pros to this method are that you can achieve a very accurate over all length and that is after all, what it is all about. The cons to this method are that you can get some variation doing it this way. Let me explain, the base is not always square to the body or can be damaged during firing especially if it is fired through a military style rifle with a very aggressive ejector. These cases should be discarded, but sometimes they can be overlooked. This condition can lead to an over all length that is incorrect. The case head being out of square will be corrected upon firing, however that case will wind up being shorter than the rest of your cases, possibly creating a difference in the neck tension on the bullet. The more you can do to eliminate variables in your reloads the better off you are going to be. This method can also be very slow, and if the user gets careless the result will be a inconsistent over all length.

Little Crow WFT

Indexing off the Shoulder (Datum Line)
The second method I mentioned, trimming off the shoulder or the datum line of the case, has its pros as well. I have found this to be the quickest of the methods and very accurate as well. After the case has been sized through the die the dimensions (particularly the headspace) of the cases are usually very uniform and exact, this allows the case to be trimmed by indexing off the shoulder. This method can be done very quickly, by hand, or by powering either the case, or the trimmer. You also don’t have to worry about the case heads being out of square with the body using this method. Generally the trimming time is cut in half, and this leads to greater focus on the job, without becoming careless. [Editor’s Note: The World’s Finest Trimmer (WFT) is one power device that indexes off the shoulder datum. It works fast and is very precise. The updated WFT 2 Model and WFT Big Boy feature interchangeable trim chambers to work with multiple cartridge types.]

Summary
The choice is yours to make. I hope that this was some help to you, whether you are looking for your first trimmer or looking to replace the trimmer you have. Just remember to always put safety first and accuracy second, and you will start making little bug holes in no time.

Story Tip by EdLongrange. User Submissions are welcome.
Permalink Reloading, Tech Tip 3 Comments »
April 26th, 2018

Digital Leveling Devices — Level Your Rifle or Check Shot Angles

Here’s a cool product that can help you level your front rest and rear bag, level your scope, align your target frame, and perform a myriad of tasks around the house. The Digital Angle Cube (aka Electronic Level and Protractor Gauge) is basically a high-tech level that gives you exact angular read-outs to within 0.2 degrees. That’s a lot more precise than any bubble level.

Numerous Shooting-Related Applications
For you position shooters who like to run angled sights, this tool will help you set the rear sight and front tower to exactly the same angle. For High Power guys with 3-way and 4-way adjustable buttstocks, this digital angle gauge can help you quickly and precisely set buttstock angle and cast-off.

Even tactical shooters and long-range hunters can use this device to confirm exact shot angle, with greater precision than a plastic protractor or even an expensive Angle Degree Indicator (ADI). Heck you can even use the thing as an anti-cant device (if you don’t mind the extra weight). We’re sure that our clever readers can find even more uses for a digital angle read-out tool.

The gray-faced iGaging Digital AngleCube sells on Amazon.com for $31.95. It comes with magnets on two sides so you can attach the tool to any ferrous metal surface for a “hands-free” reading. Amazon also sells the WATERPROOF Neoteck Digital Level for $24.95, with magnets on the base. You can find similar devices in hardware and home improvement stores. The illustration below shows how an INSIZE digital level and protractor can be used in the field.

Story based on tip by Edlongrange.
Permalink Gear Review, Tech Tip No Comments »
April 22nd, 2018

AZTEC Mode for AMP Annealer — Create Custom Brass Profiles

AMP Annealer Annealing Aztec program sorting cartridge brass annealing

New Zealand-based Annealing Made Perfect (AMP) has released powerful new software called AZTEC Mode. This works with existing AMP annealing machines, offering unrivaled “custom tuning” for your brass. AZTEC Mode lets AMP owners calibrate their own cases without sending samples to New Zealand. Basically you take one brass case from your lot, and AZTEC runs a special test cycle. You’ll discard that one case, but the software will analyze the brass characteristics and develop a custom, optimized annealing profile for that exact type of brass. We think the AMP machines were already the most advanced annealers on the market, and AZTEC Mode makes the AMP even better.

AMP’s engineers tell us: “This AZTEC system is not a firmware update or patch. It is a major upgrade in the way the annealer operates”. AZTEC Mode can be downloaded (in locked format) from AMPAnnealing.com, and you can install using the USB cable supplied with the annealer. When downloaded, it will be locked. The Unlock Code can be purchased for $250.00 from Creedmoor Sports.

This 4-minute video explains the basic features of AZTEC mode:

AMP Annealer Annealing Aztec program sorting cartridge brass annealing

Patent-Pending AZTEC Mode software has been under development for quite some time. This very sophisticated software was unveiled at SHOT Show 2018, and now it is available for download and purchase. AMP’s team has worked hard in the past few months perfecting AZTEC Mode and it’s now ready for the end user. Watch this comprehensive video to see how AZTEC Mode works.

Here is a full 23-minute Instructional Video on AZTEC Mode:

AZTEC also comes with a “Sort Mode” comparator, which analyses the neck, shoulder and front section of the body. It is very sensitive to variables such as mass and dimensions. It is a work in progress. Annealing Made Perfect are conducting further research with ballistics laboratories to establish the best applications. AZTEC Mode is self-prompting and very simple to use with minimal technical expertise. AMP has prepared instructional videos showing how to install and use AZTEC Mode. You don’t have to be a computer whiz — just follow the instructions and you should find AZTEC pretty easy to use.

To buy AZTEC Mode software, use the USB cable supplied with the annealer and download the AZTEC Mode Software from AMPAnnealing.com. Then purchase the Unlock Code from Creedmoor Sports for $250.00. Customers will then receive an email from Annealing Made Perfect with the unlock code and instructions within 48 hours. AZTEC Mode is currently only available for Windows OS, with a version for Apple (Mac) iOS available soon.

Permalink New Product, News, Tech Tip No Comments »
April 20th, 2018

Don’t Go Deaf — Understand Risks of Concussive Hearing Loss

Mark Kuczka Accurate Ordnance hearing protection dB noise muzzle brake PRS muffs earplugs concussion concussive hearing loss

Did you know you can damage your hearing even if you are wearing the best hearing protection available? Well, have you ever heard of concussion (or concussive) hearing loss? There is no amount of anything you can put in or over your ears to protect you from concussion loss. My audiologist explained to me the concussion comes through the facial bone structure and damages the ear’s tiny bones.

Editor’s NOTE: This may be the most important tech article we’ve run all year. It explains how you can suffer inner ear damage and hearing loss even if you use earplugs or muffs. Read that again — hearing loss even with typical hearing protection. This kind of concussive hearing loss can result from shooting with muzzle brakes in confined spaces. Using a suppressor (aka sound moderator) can reduce the risk of concussive hearing loss. You may not have the ability to use a suppressor, but this article explains how you should be more mindful of your hearing.

Why I Use a Suppressor (Preventing Concussive Hearing Loss)

Report by Mark Kuczka, Accurate Ordnance

It must have been the road noise. I thought I was having a hard time hearing my five year old daughter speaking to me on my cell phone because of the road noise. That old SUV was kind of loud inside. Until I switched the phone to my left ear and suddenly I could hear her just fine. Wait, what just happened? I moved the phone back to the right ear and there was that muffled voice again. That’s when I knew I had a problem.

“What?” Lots of us in the shooting community have lost some hearing along the way due to our time on the range or in the field. Those of us who hunt have certainly discharged a firearm or three without ear protection and without concern for our hearing. After all, it’s just one shot, right? How much can it hurt?

Actually, that one shot DOES hurt your hearing. Any sound over 140 dB is immediate hearing loss. It just happens to be killing a small amount of our hearing so most of us continued the practice without a care. Living with hearing loss now makes me wish I could go back 20 years and better protect my hearing. I can’t change what I did in the past, but going forward I can certainly do the most to protect the hearing I still have.

I decided to shoot about a year’s worth of matches with just braked rifles. That year is when I lost significant hearing in my right ear and some in the left. I’ve gone back to shooting only suppressed rifles whenever possible.

Mark Kuczka Accurate Ordnance hearing protection dB noise muzzle brake PRS muffs earplugs concussion concussive hearing loss

I shot my first suppressed firearm, a .22 LR pistol, in 2003. After a few rounds I wondered why everyone (who can do so legally) didn’t shoot suppressed? No one drives without a muffler. Why would you? Point is I immediately appreciated the hearing protection benefits of suppressors. That passion got me into the business of selling suppressors and it wasn’t long before I was one of the biggest retailers for companies like AAC, SWR, SilencerCo, Ops Inc. and others. [Editor: The author’s business, Accurate Ordnance, no longer sells suppressors. So this article is NOT a sales pitch. Mark just wanted to share his experience so others might protect their hearing.]

Mark Kuczka Accurate Ordnance hearing protection dB noise muzzle brake PRS muffs earplugs concussion concussive hearing loss

Did you know you can damage your hearing even if you are wearing the best hearing protection available? You’ve heard guys say, “I’ll wear plugs and muffs, so I’ll be just fine shooting that .50 BMG!” Well, ever heard of concussion (or concussive) hearing loss? Yeah, I hadn’t either. I’ll sum it up the way the last audiologist I spoke with about my hearing loss did – there is no amount of anything you can put in or over your ears to protect you from concussion loss.

A hand grenade went off right next to a buddy of mine. He lost some hearing as a result of the blast. No one is really surprised by that. I mean it is an EXPLOSION. It’s loud. Duh. But I had no idea the blast from a muzzle brake could basically hurt my hearing the same way. The doctor explained to me the concussion comes through the facial bone structure and damages the ear’s tiny bones. Same thing as what can happen through any TBI (traumatic brain injury).

Hearing loss diagram inner ear

I’ve owned quite a few different suppressors over the years and have shot just about everything out there. I’m still as big a fan as ever. However, I wanted to see if using a suppressor in PRS (Precision Rifle Series) and similar matches was actually a hindrance. Some people feel the added length and weight of a suppressor can make getting into some shooting positions slower or problematic. So I decided to shoot about a year with a muzzle brake instead of a suppressor. I sure regret that decision…

Getting Headaches at PRS Matches Was Warning Sign
It is fairly common in PRS matches to shoot through pipes, vehicles, inside “shoot houses” and around other obstacles that echo a rifle’s blast. I noticed I was starting to get headaches about halfway through a day of PRS match shooting. I knew the issue wasn’t hydration. I mean look, if you are peeing every other stage down at the amazing CORE range facility in mid-summer you are NOT dehydrated. So, what was causing the headaches? It wasn’t until I went back to shooting suppressed in those same environments that it became clear the little mini concussions from that muzzle brake was causing my headaches. And of course the doctors confirmed that.

Let me stop here and say I am NOT anti-brake. Muzzle brakes are useful tools and for some situations are the best tools. An aggressive brake can be more effective at reducing recoil than a good suppressor. A suppressor does add some recoil reduction, just not as much as most quality brakes. Don’t forget to factor other variables, such as caliber and rifle weight, into the equation though. For example, a 15-lb 6mm Creedmoor rifle doesn’t need much recoil reduction in the first place.

Mark Kuczka Accurate Ordnance hearing protection dB noise muzzle brake PRS muffs earplugs concussion concussive hearing loss

So, I started shooting matches long before the PRS even existed and always shot suppressed in those days. The suppressors made communication with a partner or RO easier and it was just a more pleasant shooting experience. On the recommendations of a few people I decided to shoot about a year’s worth of matches with just braked rifles. That year is when I lost significant hearing in my right ear and some in the left. I’ve gone back to shooting only suppressed rifles whenever possible and especially at matches. I’ve only once or twice found the extra length of the suppressor made it a little more inconvenient to run a stage, but not by much. Trust me, the points I missed were not because I took two extra seconds getting the muzzle in a port or window.

My hearing is something I value and will do everything to protect from this point forward. You’ll never again see me on a match field with an un-suppressed rifle. To me the minimal gains of running a braked rifle aren’t worth losing more hearing.

Choosing a Suppressor — What to Consider

Okay, so I have hearing loss that I can’t get back and realize I need to go back to shooting matches with a suppressor. But which one? I’ll still be shooting matches with custom fit plugs so I just need something to add a little recoil reduction and kill that concussion.

At our shop, Accurate Ordnance, we generally recommend direct-thread suppressor solutions to our customers. The main reason for that is all the problems we’ve seen with other fast-attach muzzle devices. It doesn’t take much tolerance stacking to result in accuracy issues. There are a few exceptions for us and the Rugged Suppressors products top the list. Since the Razor 762 uses a muzzle brake adapter on the rifle to attach the suppressor, I can use the same suppressor on my .223 Rem training rifle. My primary match rifles are chambered in 6mm Creedmoor and 6.5 Creedmoor and the muzzle threads on those is a standard 5/8×24. My .223 Rem training rifle has .5×28 threads on the muzzle, which is standard for that caliber. Thus, the muzzle adapter interface lets me share the suppressors between all the rifles. And on that .223 Rem training rifle I have the option of switching the end cap on any of the Rugged products to a .223 aperture size, which makes the suppressors slightly more sound efficient (meaning quieter).

Permalink - Articles, Competition, Tactical, Tech Tip 6 Comments »
April 18th, 2018

TECH Tip: TOP TEN Ways to Dry Wet Cartridge Brass

Wet Tumbling Brass Drier

Many shooters these days clean their cartridge brass ultrasonically, or wet-tumble their cases with stainless media (above). Both methods get brass clean and shiny, inside and out. However, when those wet-cleaning processes are completed, you’re left with a pile of soaking wet brass. How do you dry your brass quickly and efficiently, without unsightly water spots? Read on for some great answers…

In our Shooters’ Forum, Forum Gold Member Terry asked: “How do you dry your brass after Ultrasonic cleaning?” In an interesting Reloading Forum Thread, many smart suggestions were posted. A dozen fellow members outlined a variety of effective case-drying procedures, which work equally well for both wet-tumbled brass and ultrasonically-cleaned cases. Here are the Top 10 brass-drying suggestions from our Forum members.

TOP TEN Ways to Dry Cartridge Brass After Wet Cleaning

1. Food Dehydrator — Shake the brass in towel to get the bulk of water off. Next leave in the food dehydrator for 45 minutes or until there are no signs of moisture inside the cases. — Lawrence97

2. Lyman 5-Level Case Dryer — Rinse off cleaning solution(s), then load brass by type into racks in Lyman Cyclone Case Dryer. This is easier to load/unload than food dehydrators and holds more cases.

Lyman Cyclone Case Drier

3. Hot Water + Compressed Air — Rinse all your cases as a batch using scalding hot water from the kitchen sink. Hot water evaporates off of brass very very quickly. Then hit them with compressed air. Takes 10 minutes. Simple. — SG4247

4. Oven Dry in Pre-Heated Oven — After pre-heating to 200° or so, turn off oven and put brass inside on a tray. Most important! Tell your wife what you are doing so she doesn’t crank it up to 425 to heat pizza! — MClark

NOTE: Many other members suggested oven drying at 150-200°. We recommend turning OFF the oven so you don’t cook your brass if you forget to remove the cases.

Dry Cartridge Brass heat gun5. Towel Dry then Warm with Heat Gun — Roll brass in a towel until no more water shakes out. Lay out on cardboard box top and blow off with Harbor Freight heat gun. $9.99 on coupon. Two minutes of heated air and about half hour of wait and they are good to go. This is with primers removed. — Shaggy357

6. Compressed Air, then Sun Dry Outside – I rinse the brass, then blow them out with compressed air. Then, dependent on the time of year, lay them on a towel in the sun. — HogPatrol

7. Dishwasher on Dry Cycle – In the winter, I drop my wet brass cases neck-down on the rack pegs in the dishwasher, then turn on the dry cycle. In the summer…well, I’m in Texas. They go to the porch for a bit. — Toolbreaker

8. Alcohol Rinse then Air or Oven Dry — Rinse in 90% Isopropyl alcohol and either let air dry or stick in 175° oven for half an hour. Alternatively, use a dehydrator. — Zipollini

9. Slow Air-Dry in Loading Blocks — I have a reloading block with holes drilled in it. I simply load the block up and let it air-dry in the cupboard for a couple of days. — JCS

10. Wipe with Towel Then Anneal Normally — This thread is stirring my OCD side. Seems complicated for just drying — my brass dries just fine when I anneal it. This entire process can’t take an hour per batch. When finished, the brass is cleaned, annealed, and ready to size. — CHLuke

  • Deprime, then tumble brass with stainless media, water, Lemishine, and dish detergent.
  • Shake them easily in a strainer to knock out most media then grab 4-5 pieces, shake them over the bucket for the last of the media then inside a towel.
  • Finally blow out the primer pockets and wipe with a towel, load in the Annealeez.

Wet Tumbling Brass Drier

Permalink Bullets, Brass, Ammo, Reloading, Tech Tip 7 Comments »
April 17th, 2018

If You’re Not Using Wind Flags You’re Throwing Away Accuracy


Forest of Windflags at World Benchrest Championships in France in 2011

There’s a simple, inexpensive “miracle device” that can cut your groups in half. If you’re not using this device, you’re giving away accuracy. The “miracle device” to which we refer is a simple wind indicator aka “windflag”. Using windflags may actually improve your accuracy on target much more than weighing charges to the kernel, or spending your life savings on the “latest and greatest” hardware.

Remarkably, many shooters who spend $3000.00 or more on a precision rifle never bother to set up windflags, or even simple wood stakes with some ribbon to show the wind. Whether you’re a competitive shooter, a varminter, or someone who just likes to punch small groups, you should always take a set of windflags (or some kind of wind indicators) when you head to the range or the prairie dog fields. And yes, if you pay attention to your windflags, you can easily cut your group sizes in half. Here’s proof…

Miss a 5 mph Shift and You Could DOUBLE Your Group Size

The table below records the effect of a 5 mph crosswind at 100, 200, and 300 yards. You may be thinking, “well, I’d never miss a 5 mph let-off.” Consider this — if a gentle 2.5 mph breeze switches from 3 o’clock (R to L) to 9 o’clock (L to R), you’ve just missed a 5 mph net change. What will that do to your group? Look at the table to find out.

shooting wind flags
Values from Point Blank Ballistics software for 500′ elevation and 70° temperature.

Imagine you have a 6mm rifle that shoots half-MOA consistently in no-wind conditions. What happens if you miss a 5 mph shift (the equivalent of a full reversal of a 2.5 mph crosswind)? Well, if you’re shooting a 68gr flatbase bullet, your shot is going to move about 0.49″ at 100 yards, nearly doubling your group size. With a 105gr VLD, the bullet moves 0.28″ … not as much to be sure, but still enough to ruin a nice small group. What about an AR15, shooting 55-grainers at 3300 fps? Well, if you miss that same 5 mph shift, your low-BC bullet moves 0.68″. That pushes a half-inch group well past an inch. If you had a half-MOA capable AR, now it’s shooting worse than 1 MOA. And, as you might expect, the wind effects at 200 and 300 yards are even more dramatic. If you miss a 5 mph, full-value wind change, your 300-yard group could easily expand by 2.5″ or more.

If you’ve already invested in an accurate rifle with a good barrel, you are “throwing away” accuracy if you shoot without wind flags. You can spend a ton of money on fancy shooting accessories (such as expensive front rests and spotting scopes) but, dollar for dollar, nothing will potentially improve your shooting as much as a good set of windflags, used religiously.

Which Windflag to buy? Click Here for a list of Vendors selling windflags of various types.

Aussie Windflag photo courtesy BenchRestTraining.com (Stuart and Annie Elliot).

Permalink Shooting Skills, Tech Tip 1 Comment »
April 12th, 2018

Finger-Painting to CNC Inletting — Inside Look at McMillan Stocks

McMillan Fiberglass stocks factory videosOK, admit it — you’ve always wondered how they get those color swirls and camo patterns in McMillan stocks. (You’ll be surprised at the answer). And how does McMillan manage to inlet stocks so precisely for so many different action types?

McMillan Stocks is one of the leading fiberglass stock producers, cranking out 8,000-10,000 stocks every year for hunters, target shooters, and members of the military. McMillan employs state-of-the-art, high-tech machinery. At the same time, many processes are still done by hand — such as applying colors to the stocks.

In the videos below, Kelly McMillan hosts Bob Beck of Extreme Outer Limits TV in a tour of the McMillan stock-making facility. We think all avid “gun guys” will be fascinated by these high-quality videos.

McMillan Custom Stock Production

The first video shows the stock-building operation from start to finish — You’ll see the lay-up, color application, molding, and “stuffing”. Watch carefully at 0:16 to see colors being applied.

(more…)

Permalink - Videos, Gunsmithing, Tech Tip 1 Comment »
April 6th, 2018

TECH TIP — Check Barrel Tightness If POI Shifts Erratically

loose barrel vortex scope optics point of impact change fix

Are you seeing unpredictable changes in Point of Impact on your target? Think you may have a scope issue? Well maybe not — when was the last time you checked your BARREL?

Yes scopes do fail, and scope bases/rings do get loose. But sometimes problems with erratic POI shifts are caused by a LOOSE BARREL. This issue came up recently in our Shooter’s Forum. One member complained that his zero was shifting from day to day — by as much as two inches at 100 yards. He was convinced he had a scope problem, based on erratic POI:

“I think my scope loses 1 to 3 MOA per day. When I shot my rifle Monday it was dead on. On Tuesday it was 1″ low. Then on Wednesday it was 1 or 2″ lower. I don’t get it. — the elevation knob never touched. Scope will track and return to zero that day perfect. Yes EVERYTHING has been checked, nothing loose. What is the chance the erector tube spring has gone south? For the record this is a Vortex GE. Never had a bad scope, but this has me wondering”. — LB

On Forum member told LB to send the scope right back to the manufacturer. Two other members suggested mounting the scope on a different rifle to test. Good advice. That’s generally a smart strategy before you conclude a scope has gone bad…

Could Problem Be the Scope Base?
Two Forum members, ExPiper and Dickn52, suggested checking the scope base, recounting their past experiences with troublesome bases. This was intelligent — anyone with a POI problem should check all the optics attachments:

“Went crazy one day chasing my impacts on a 100-yard target. Shots would group fine for three then go nuts for 4-5. I cranked and un-cranked for about an hour. Then I reached up and the base wobbled on the rifle. Removed scope, tightened base screws and back in business.” — Dickn52

“Years ago I had a problem [where] shots were climbing with almost every shot. I was blaming the scope. However, when removing the scope I noticed that the 20 MOA base was cracked and getting wider with every shot. Needless to say I replaced the base and the problem was solved. — ExPiper

Eureka Moment — The problem was the BARREL, not the Scope

There were many helpful suggestions, but member PirateAmmo steered LB to the real problem — a loose BARREL: “We had a problem on a home-built AR-platform rifle once, barrel was loose a tad…”

Member Snert chimed in: “Yep — I had a PPC that suddenly went 19″ low. Picked up gun off bench by barrel and felt a wiggle. I tightened the barrel and the POI went 19 inches up”.

Problem Solved — Barrel Tightened up and POI Back to Normal
The gentleman with the POI problem took the advice of PirateAmmo and checked his barrel. BINGO! Low and behold, the barrel WAS loose.

LB posted: “Barrel loose by about 2%, checked it twice before and didn’t find it the first two times”.

After LB re-tightened his barrel, his rifle started shooting normally again. No more shooting low by 1-2 inches. Problem solved. The fix didn’t cost a penny and now LB doesn’t have to send a perfectly good optic back to the manufacturer.

Lesson learned? Check ALL the variables before you assume a scope has gone bad. Along with the barrel, also check your action screw tension, and of course the scope base and rings.

Permalink Optics, Tech Tip 3 Comments »
April 6th, 2018

Know Your Terminology — CUP vs. PSI

SAAMI CUP PSI Cartridge Copper Units Pressure PSI
Image by ModernArms, Creative Common License.

by Philip Mahin, Sierra Bullets Ballistic Technician
This article first appeared in the Sierra Bullets Blog

If you asked a group of shooters to explain the difference between CUP and PSI, the majority would probably not be able to give a precise answer. But, for safety reasons, it’s very important that all hand-loaders understand these important terms and how they express cartridge pressures.

The ANSI / SAAMI group, short for “American National Standard Institute” and “Sporting Arms and Ammunition Manufacturers’ Institute”, have made available some time back the voluntary industry performance standards for pressure and velocity of centerfire rifle sporting ammunition for the use of commercial manufacturers. [These standards for] individual cartridges [include] the velocity on the basis of the nominal mean velocity from each, the maximum average pressure (MAP) for each, and cartridge and chamber drawings with dimensions included. The cartridge drawings can be seen by searching the internet and using the phrase ‘308 SAAMI’ will get you the .308 Winchester in PDF form. What I really wanted to discuss today was the differences between the two accepted methods of obtaining pressure listings. The Pounds per Square Inch (PSI) and the older Copper Units of Pressure (CUP) version can both be found in the PDF pamphlet.

SAAMI CUP PSI Cartridge Copper Units Pressure PSICUP Pressure Measurement
The CUP system uses a copper crush cylinder which is compressed by a piston fitted to a piston hole into the chamber of the test barrel. Pressure generated by the burning propellant causes the piston to move and compress the copper cylinder. This will give it a specific measurable size that can be compared to a set standard. At right is a photo of a case that was used in this method and you can see the ring left by the piston hole.

PSI Pressure Measurement
What the book lists as the preferred method is the PSI (pounds per square inch or, more accurately, pound-force per square inch) version using a piezoelectric transducer system with the transducer flush mounted in the chamber of the test barrel. Pressure developed by the burning propellant pushes on the transducer through the case wall causing it to deflect and make a measurable electric charge.

Q: Is there a standardized correlation or mathematical conversion ratio between CUP and PSI values?
Mahin: As far as I can tell (and anyone else can tell me) … there is no [standard conversion ratio or] correlation between them. An example of this is the .223 Remington cartridge that lists a MAP of 52,000 CUP / 55,000 PSI but a .308 Winchester lists a 52,000 CUP / 62,000 PSI and a 30-30 lists a 38,000 CUP / 42,000 PSI. It leaves me scratching my head also but it is what it is. The two different methods will show up in listed powder data[.]

So the question on most of your minds is what does my favorite pet load give for pressure? The truth is the only way to know for sure is to get the specialized equipment and test your own components but this is going to be way out of reach for the average shooter, myself included. The reality is that as long as you are using printed data and working up from a safe start load within it, you should be under the listed MAP and have no reason for concern. Being specific in your components and going to the load data representing the bullet from a specific cartridge will help get you safe accuracy. [With a .308 Winchester] if you are to use the 1% rule and work up [from a starting load] in 0.4 grain increments, you should be able to find an accuracy load that will suit your needs without seeing pressure signs doing it. This is a key to component longevity and is the same thing we advise [via our customer service lines] every day. Till next time, be safe and enjoy your shooting.

SAAMI CUP PSI Cartridge Copper Units Pressure PSI

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