In this detailed 22-minute video, John McQuay of 8541 Tactical shows how to input firearm specs, MV, and BC into a Kestrel 4500 NV (Applied Ballistics model). This handy unit combines a Kestrel Weather meter with a full-fledged ballistics computer.
Step-by-step the video shows how to set up all the important variables. The video shows how to input Muzzle Velocity, Bullet BC (G1 or G7), Zero Distance and the other key ballistics variables. In addition, the video explains how to input gun-specific data such as bore height, barrel twist rate, and barrel rifle twist direction (right-hand vs. left-hand). (Twist direction comes into play in long range spin drift calculations).
If you own a Kestrel 4500 NV (Applied Ballistics), we think you’ll find this video helpful — particularly when it comes to setting up some of the lesser-known data items. The video also offers tips on navigating through the menus most efficiently.
Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. This USAMU “Handloading Hump Day” article, the second in a series on improving concentricity, has many useful tips. If you use standard (non-micrometer) seating dies when loading some cartridge types, this article is worth reading. And visit the USAMU Facebook page next Wednesday for the next installment.
Once again, it’s time for USAMU’s “Handloading Hump-Day!” Last week, we addressed achieving very good loaded-cartridge concentricity (AKA “TIR”, or Total Indicator Runout) using standard, “hunting grade” reloading dies.
We explained how to set up the Full-Length Size die to float slightly when correctly adjusted for desired case headspace. We also cited a study in which this method loaded ammunition straighter than a set of [higher grade] match dies from the same maker. [One of the keys to reducing TIR with both sets of dies was using a rubber O-ring below the locking ring to allow the die to float slightly. READ Full-Length Sizing Die TIP HERE.]
Now, we’ll set up a standard seating die to minimize TIR — the other half of the two-die equation. As before, we’ll use a single-stage press since most new handloaders will have one. A high-quality runout gauge is essential for obtaining consistent, accurate results.
Having sized, primed and charged our brass, the next step is bullet seating. Many approaches are possible; one that works well follows. When setting up a standard seating die, insert a sized, trimmed case into the shell-holder and fully raise the press ram. Next, back the seating stem out and screw the die down until the internal crimping shoulder touches the case mouth.
Back the die out one-quarter turn from this setting to prevent cartridge crimping. Next, lower the press ram and remove the case. Place a piece of flat steel on the shellholder and carefully raise the ram. Place tension on the die bottom with the flat steel on the shellholder. This helps center the die in the press threads. Check this by gently moving the die until it is well-centered. Keeping light tension on the die via the press ram, secure the die lock ring.
If one were using a micrometer-type seating die, the next step would be simple: run a charged case with bullet on top into the die and screw the seating stem down to obtain correct cartridge OAL.
However, with standard dies, an additional step can be helpful. When the die has a loosely-threaded seating stem, set the correct seating depth but don’t tighten the stem’s lock nut. Leave a loaded cartridge fully raised into the die to center the seating stem. Then, secure the stem’s lock nut. Next, load sample cartridges and check them to verify good concentricity.
One can also experiment with variations such as letting the seating stem float slightly in the die to self-center, while keeping correct OAL. The runout gauge will show any effects of changes upon concentricity. However, the first method has produced excellent, practical results as evidenced by the experiment cited previously. These results (TIR Study 2) will reproduced below for the reader’s convenience.
TIR Study 2: Standard vs. Match Seating Dies
50 rds of .308 Match Ammo loaded using carefully-adjusted standard dies, vs. 50 using expensive “Match” dies from the same maker.
Standard dies, TIR:
0.000” — 0.001” = 52%;
0.001”– 0.002” = 40%;
0.002”– 0.003” = 8%. None greater than 0.003”.
AccurateShooter Comment: This shows that, with careful adjustment, the cheaper, standard dies achieved results that were as good (or better) than the more expensive “Match” Dies.
These tips are intended to help shooters obtain the best results from inexpensive, standard loading dies. Especially when using cases previously fired in a concentric chamber, as was done above, top-quality match dies and brass can easily yield ammo with virtually *no* runout, given careful handloading.
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Here’s a great tip from Forum member Greg C. (aka “Rem40X”). Greg has created a trajectory table with windage and elevation data for various distances and wind speeds. Greg prints out a compact version of his drop chart to place on his rifle. While many shooters tape a ‘come-up’ table on their buttstock, Greg has a better solution. He tapes the trajectory table to the outside of his front flip-up scope cover. This way, when he flips up the cover, his data is displayed for easy viewing right in front.
With your ‘come-up’ table on the flip-up cover you can check your windage and elevation easily without having to move up off the rifle and roll the gun over to look at the side of the stock. Greg tells us: “Placing my trajectory table on the front scope cover has worked well for me for a couple of years and thought I’d share. It’s in plain view and not under my armpit. And the table is far enough away that my aging eyes can read it easily. To apply, just use clear tape on the front objective cover.”
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We’ve all seen them — you know those guys who don’t follow range rules, or who handle firearms in a careless manner. Sometimes bad range etiquette is simply annoying. Other times poor gun-handling practices can be downright dangerous. The NRA Blog has published a useful article about range safety and “range etiquette”. While these tips were formulated with indoor ranges in mind, most of the points apply equally well to outdoor ranges. You may want to print out this article to provide to novice shooters at your local range or club.
8 Tips for Gun Range Etiquette
Story by Kyle Jillson for NRABlog
Here are eight tips on range etiquette to keep yourself and others safe while enjoying your day out [at the range]. Special thanks to NRA Headquarters Range General Manager Michael Johns who assisted with this article.
1. Follow the Three Fundamental Rules for Safe Gun Handling
ALWAYS keep the gun pointed in a safe direction.
ALWAYS keep your finger off the trigger until ready to shoot.
ALWAYS keep the gun unloaded until ready to use.
2. Bring Safety Gear (Eye and Ear Protection)
Eye and Ear protection are MANDATORY for proper safety and health, no matter if “required” by range rules or not. It is the shooter’s responsibility to ensure proper protection is secured and used prior to entering/using any range. Hearing loss can be instantaneous and permanent in some cases. Eyesight can be ruined in an instant with a catastrophic firearm failure.
3. Carry a Gun Bag or Case
Common courtesy and general good behavior dictates that you bring all firearms to a range unloaded and cased and/or covered. No range staff appreciates a stranger walking into a range with a “naked” firearm whose loaded/unloaded condition is not known. You can buy a long gun sock or pistol case for less than $10.
4. Know Your Range’s Rules
Review and understand any and all “range specific” rules/requirements/expectations set forth by your range. What’s the range’s maximum rate of fire? Are you allowed to collect your brass? Are you required to take a test before you can shoot? Don’t be afraid to ask the staff questions or tell them it’s your first time. They’re there to help.
5. Follow ALL Range Officer instructions
ROs are the first and final authority on any range and their decisions are generally final. Arguing/debating with a Range Officer is both in poor taste and may just get you thrown out depending on circumstances.
6. Don’t Bother Others or Touch Their Guns
Respect other shooters’ privacy unless a safety issue arises. Do NOT engage other shooters to correct a perceived safety violation unless absolutely necessary – inform the RO instead. Shooters have the right and responsibility to call for a cease fire should a SERIOUS safety event occur. Handling/touching another shooter’s firearm without their permission is a major breech of protocol. Offering unsolicited “training” or other instructional suggestions to other shooters is also impolite.
7. Know What To Do During a Cease Fire
IMMEDIATELY set down your firearm, pointed downrange, and STEP AWAY from the shooting booth (or bench). The Range Officer(s) on duty will give instructions from that point and/or secure all firearms prior to going downrange if needed. ROs do not want shooters trying to “secure/unload” their firearms in a cease fire situation, possibly in a stressful event; they want the shooters separated from their guns instantly so that they can then control the situation as they see fit.
8. Clean Up After Yourself
Remember to take down your old targets, police your shooting booth, throw away your trash, and return any equipment/chairs, etc. Other people use the range too; no one wants to walk up to a dirty lane.
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Hunters and tactical shooters need scopes with good low-light performance. For a scope to perform well at dawn and dusk, it needs good light transmission, plus a reasonably large exit pupil to make maximum use of your eye’s light processing ability. And generally speaking, the bigger the front objective, the better the low-light performance, other factors being equal. Given these basic principles, how can we quickly evaluate the low-light performance of different makes and models of scopes?
Here’s the answer: ScopeCalc.com offers a FREE web-based Low-Light Performance Calculator that lets you compare the light gain, perceived brightness, and overall low-light performance of various optics. Using this scope comparison tool is pretty easy — just input the magnification, objective diameter, exit pupil size, and light transmission ratio. If the scope’s manufacturer doesn’t publish an exit pupil size, then divide the objective diameter in millimeters by the magnification level. For example a 20-power scope with a 40mm objective should have a 2mm exit pupil. For most premium scopes, light transmission rates are typically 90% or better (averaged across the visible spectrum). However, not many manufacturers publish this data, so you may have to dig a little.
ScopeCalc.com’s calculator can be used for a single scope, a pair of scopes, or multiple scopes. Once you’ve typed in the needed data, click “Calculate” and the program will produce comparison charts showing Light Gain, Perceived Brightness, and Low-Light Performance. Though the program is easy to use, and quickly generates comparative data, assessing scope brightness, as perceived by the human eye, is not a simple matter. You’ll want to read the annotations that appear below the generated charts. For example, ScopeCalc’s creators explain: “Perceived brightness is calculated as the cube root of the light gain, which is the basis for modern computer color space brightness scaling.”
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Do you have some old, tired brass that needs a thorough cleaning — inside and out? Consider using an ultrasonic cleaning machine. When used with the proper solution, a good ultrasonic cleaning machine can quickly remove remove dust, carbon, oil, and powder residue from your cartridge brass. The ultrasonic process will clean the inside of the cases, and even the primer pockets. Tumbling works well too, but for really dirty brass, ultrasonic cleaning may be a wise choice.
Our friend Gavin Gear recently put an RCBS Ultrasonic cleaning machine through its paces using RCBS Ultrasonic Case Cleaning Solution (RCBS #87058). To provide a real challenge, Gavin used some very dull and greasy milsurp brass: “I bought a huge lot of military once-fired 7.52x51mm brass (fired in a machine gun) that I’ve been slowly prepping for my DPMS LR-308B AR-10 style rifle. Some of this brass was fully prepped (sized/de-primed, trimmed, case mouths chamfered, primer pockets reamed) but it was gunked up with lube and looking dingy.”
UltimateReloader.com Case Cleaning Video (7.5 minutes):
Gavin describes the cleaning exercise step-by-step on UltimateReloader.com. Read Gavin’s Cartridge Cleaning Article to learn how he mixed the solution, activated the heater, and cycled the machine for 30 minutes. As you can see in the video above, the results were impressive. If you have never cleaned brass with ultrasound before, you should definitely watch Gavin’s 7.5-minute video — it provides many useful tips and shows the cleaning operation in progress from start to finish.
The RCBS ultrasonic cleaning machine features a large 3-liter capacity, 60 watt transducer, and 100 watt ceramic heater. The RCBS ultrasonic machine can be found under $140.00, and this unit qualifies for RCBS Rebates ($10 off $50 purchase or $50 off $300.00 purchase). RCBS also sells 32 oz. bottles of cleaning concentrate that will make up to 10 gallons of Ultrasonic Solution.
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by Tony Chow
In recent years, the use of electronic trainer systems has revolutionized training in all disciplines of position shooting. By capturing (and illustrating) key performance variables like the steadiness of a shooter’s hold, accuracy of aiming, and the timeliness of trigger release, these devices can offer tremendous insights into the strengths and weakness of a shooter’s position and technique, making high-level marksmanship training less voodoo and more of a science.
Until now, electronic trainers all suffered from one critical limitation: the inability to be used outdoors in live fire training. Now, however, SCATT has introduced the next-generation MX-02 electronic trainer, a product that can finally support outdoor live firing in broad daylight, as well as dry firing indoors. In addition, the MX-02 is the first electronic trainer to support centerfire rifles. It goes without saying that, when we at AccurateShooter.com were offered an MX-02 test unit to review, we jumped at the opportunity.
How the SCATT MX-02 Works
The SCATT sensor mounted on the end of the barrel has a digital camera that “sees” the black bullseye in the target, even in broad daylight outdoors. Using the bullseye as a reference, the SCATT software tracks the movement of the muzzle relative to the center of the target. The unit can plot these movements as a continuous trace, which appears on a monitor as a squiggly, colored line. Data points from the trace are also available in a tabular spreadsheet format. This allows the shooter to “crunch the numbers”, revealing strengths and weaknesses in his gun-handling and aiming technique.
In our testing, we confirmed that, like SCATT’s earlier indoor-only WS-01, the MX-02 offers excellent support for indoor dry-fire training, which will continue to be the primary means through which position shooters sharpen their fundamental skills. Since the new SCATT uses the same familiar Windows software for data capture and analysis as its predecessors, shooters and coaches upgrading to MX-02 will have no learning curve to overcome, and newcomers to the SCATT platform can tap into the wealth of institutional knowledge accumulated over the years by the shooting community on how to interpret shot data.
It’s in the support for outdoor live firing, however, that SCATT MX-02 distinguishes itself from its predecessors and the competition. Shot trace data captured by MX-02 during live firing turned out to be every bit as valuable (and revealing) as we had hoped. The ability to correlate SCATT tracing with real shots on target gave us a better understanding of the shooting process, and helped the reviewer, already a high-level smallbore prone shooter, uncover a significant problem in his shooting. SCATT MX-02’s outdoor capability is therefore an invaluable feature, particularly for experienced shooters aspiring to world-class performance.
In summary, SCATT MX-02 is an outstanding product that delivers on its promises. We heartily recommend it, both for first-time users of electronic training aids, and also for those shooters who may wish to upgrade their current electronic training system. The MSRP for SCATT MX-02 is $1,799, $500 more than its predecessor, the SCATT WS-01, which is still available. In my view, the $500 premium for the MX-02 is justified by the MX-02’s enhanced capabilities, making it a better long-term investment.
Our complete, 3600-word MX-02 review of the SCATT MX-02 can be accessed through the link below. This full review contains many more photos plus detailed field test results. For the time being, the review only covers our experience with the product in smallbore shooting. An upcoming addendum to the review will include test results from centerfire shooting. Those attending SHOT Show in Las Vegas next week can examine SCATT MX-02 in person. SCATT will have the MX-02 on display at Booth 111.
Many 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 will probably average consistently 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 much better selection of high-BC projectiles, and will 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. Plus, for most people, the 6BR is just easier to shoot than a .308. Recoil is less than half of the .308 cartridge. Both the .308 and 6BR chamberings offer good barrel life, but the 6BR uses 15-18 grains less powder, saving you money. On the other hand the .308 is the designated cartridge for F-TR and Palma shooting, so it may be a more versatile chambering for Long-Range competition. So which would we choose between the 6BR and the .308? Actually we think you should have both. The 6BR is my favorite cartridge out to 500 yards, and I like the .308 Win for F-TR. And… if you want to shoot at the World Fullbore Championships this week at Camp Perry there’s only one choice — a .308 Win.
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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.
1. 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 have a piece of tape that I’ve placed on the golf shaft that indicates how far the back end of the rear bag should be placed from the front rest stop. Don’t have an old golf shaft? Go to Home Depot and buy an inexpensive piece of 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.
5. 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 with a low-recoiling rimfire rifle, action screws or scope rings can come loose during normal shooting.
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.
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A Kestrel Wind Meter will record wind speed with its impeller wheel. However, to get the most accurate wind velocity reading, you need to have your Kestrel properly aligned with the wind direction. To find wind direction, first orient the Kestrel so that the impeller runs at minimal speed (or stops), and only then turn the BACK of the Kestrel into the wind direction. Do NOT simply rotate the Kestrel’s back panel looking for the highest wind speed reading — that’s not the correct method for finding wind direction. Rotate the side of the Kestrel into the wind first, aiming for minimal impeller movement. The correct procedure is explained below by the experts at Applied Ballistics.
How to Find the Wind Direction with a Kestrel Wind Meter
Here is the correct way to determine wind direction with a Kestrel wind meter when you have no environmental aids — no other tools than a Kestrel. (NOTE: To determine wind direction, a mounted Wind Vane is the most effective tool, but you can also look at flags, blowing grass, or even the lanyard on your Kestrel).
Step 1: Find the wind’s general direction.
Step 2: Rotate the Wind Meter 90 degrees, so that the wind is impacting the side (and not the back) of the wind meter, while still being able to see the impeller.
Step 3: Fine-tune the direction until the impeller drastically slows, or comes to a complete stop (a complete stop is preferred). If the impeller won’t come to a complete stop, find the direction which has the lowest impact on the impeller.
Step 4: Turn the BACK of the Kestrel towards the direction from which the wind is blowing. Then press the capture button, and record your wind speed.
Do NOT simply point the Kestrel’s back into the wind until you get the highest wind speed — that’s not the correct method.
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The Swarovski Optik website features a blog with interesting technical articles. In the “On Target” series of blog stories, Swarovski has provided a handy explanation of how optics systems work, with exploded diagrams of rifle scopes, spotting scopes, and binoculars. CLICK HERE for Swarovski Optics Blog.
Scope Terminology Focusing Lens
The focusing lens is an adjustable lens inside the optical system for focusing the image at different distances…. In the case of rifle scopes, apart from focusing, the focusing lens also facilitates parallax compensation.
For rifle scopes, the reticle can be focused using the diopter adjustment on the eyepiece, thereby correcting any visual impairment. [Editor’s Note: Movable eyepiece diopter adjustment is not offered on all rifle scopes. It is a useful feature on Swarovski and other premium scopes. This allows shooters who need eyeglasses to get a sharply focus image even without wearing corrective lenses. Of course shooters should always wear ANSI-certified eye protection. With the diopter, folks who need correction can use inexpensive, non-Rx safety eyewear instead of expensive prescription safety glasses.]
The purpose of the reversal system is to reverse the image by means of prisms in binoculars and telescopes, and lenses in rifle scopes….The lens reversal system is needed in rifle scopes to control the variable magnification and move the exit pupil[.]
Resource tip by EdLongRange. We welcome reader submissions.
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How do you build better (more precise) ammo drop tables? With radar, that’s how. Barnes Bullets is using Doppler Radar to develop the drop tables for its new Precision Match line of factory ammunition. The Doppler radar allows Barnes to determine actual velocities at hundreds of points along a bullet’s flight path. This provides a more complete view of the ballistics “behavior” of the bullet, particularly at long range. Using Doppler radar, Barnes has learned that neither the G1 nor G7 BC models are perfect. Barnes essentially builds a custom drag curve for each bullet using Doppler radar findings.
Use of Doppler Radar to Generate Trajectory Solutions
by Barnes Bullets, LLC
Typical trajectory tables are generated by measuring only two values: muzzle velocity, and either time-of-flight to a downrange target, or a second downrange velocity. Depending on the test facility where this data is gathered, that downrange target or chronograph may only be 100 to 300 yards from the muzzle. These values are used to calculate the Ballistic Coefficient (BC value) of the bullet, and the BC value is then referenced to a standardized drag curve such as G1 or G7 to generate the trajectory table.
This approach works reasonably well for the distances encountered in most hunting and target shooting conditions, but breaks down rapidly for long range work. It’s really an archaic approach based on artillery firings conducted in the late 1800s and computational techniques developed before the advent of modern computers.
There is a better approach which has been utilized by modern militaries around the world for many years to generate very precise firing solutions. Due to the sizeable investment required, it has been slow to make its way into the commercial market. This modern approach is to use a Doppler radar system to gather thousands of data points as a bullet flies downrange. This radar data is used to generate a bullet specific drag curve, and then fed into a modern 6 Degree of Freedom (DOF) [ballistics software program] to generate precise firing solutions and greatly increase first-round hit probability. (The 6 DOF software accounts for x, y, and z position along with the bullet’s pitch, yaw, and roll rates.)
Barnes has invested heavily in this modern approach. Our Doppler radar system can track bullets out to 1500 meters, recording the velocity and time of flight of that bullet every few feet along the flight path. Consider the graph below showing a bullet specific drag curve referenced to the more common G1 and G7 curves:
Neither of the standard curves is a particularly good match to our test bullet. In the legacy approach to generating a downrange trajectory table, the BC value is in effect a multiplier or a fudge factor that’s used to shift the drag curve of the test bullet to try and approximate one of the standard curves. This leads to heated arguments as to which of the standardized drag curves is a better fit, or if multiple BC values should be used to better approximate the standard curve (e.g., use one BC value when the velocity is between Mach 1 and Mach 2, and a different BC value when the velocity is between Mach 2 and Mach 3.) Barnes’ approach to creating trajectory tables is to generate bullet-specific drag curves, and use that data directly in a modern, state-of-the-art, 6 DOF ballistics program called Prodas to generate the firing solution.
Story tip from EdLongrange. We welcome reader submissions.
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Here’s a smart new product that could save your life (or the life of a loved one). The EPIC-id bracelet stores your vital information on a shockproof, weatherproof USB flash drive that can be instantly accessed by an EMT or doctor. Your Editor just bought two of these med-info bracelets — one for himself and another for a diabetic family member. If you’re a shooter, or spend much time outdoors, you should have this device or some other kind of tag that provides your vital info (such as blood type and drug allergies) to first responders.
If you’re injured, first responders need to know if you have a medical condition, have drug allergies, or take any medications. With this bracelet, that vital info is available even if you can’t communicate. The EPIC-id Emergency Band stores medical data on a USB flash drive that can be “read” by any computer or mobile device with a USB port. Firefighters, EMTs, and medical professionals can instantly determine your name, emergency contacts, insurance, and medical information. (Read my experience below).
It’s easy to load your medical data on to the device. Standardized emergency info forms come pre-loaded — just insert the Epic-ID into any computer to fill out the forms. PC and Mac™ compatible, the waterproof EPIC-id features a durable stainless steel clasp and trim-to-fit silicone band.
Editor’s Story — Why This Is Important
Just this past Wednesday July 8th, at 2:00 am, a family member was rushed to the hospital after suffering a stroke. She was non-responsive and unable to communicate at all. This created problems for EMTs because they were unaware of her current medications, insulin needs, resusitation preferences, and some relevant past medical history. After that experience I decided to buy these bracelets for her and myself. The good new is that she survived… but it was close.
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So what does a “worn-out” barrel really look like? Tom Myers answered that question when he removed a 6.5-284 barrel and cut it down the middle to reveal throat wear. As you can see, there is a gap of about 5mm before the lands begin and you can see how the lands have thinned at the ends. (Note: even in a new barrel, there would be a section of freebore, so not all the 5mm gap represents wear.) There is actually just about 2mm of lands worn away. Tom notes: “Since I started out, I’ve chased the lands, moving out the seating depth .086″ (2.18 mm). I always seat to touch. My final touch dimension was 2.440″ with a Stoney Point .26 cal collet.”
Except for the 2mm of wear, the rifling otherwise looks decent, suggesting that setting back and rechambering this barrel could extend its useful life. Tom reports: “This was something I just thought I’d share if anyone was interested. I recently had to re-barrel my favorite prone rifle after its scores at 1,000 started to slip. I only ever shot Sierra 142gr MatchKings with VV N165 out of this barrel. It is a Hart and of course is button-rifled. I documented every round through the gun and got 2,300 over four years. Since I have the facilities, I used wire EDM (Electro Discharge Machining) to section the shot-out barrel in half. It was in amazingly good shape upon close inspection.”
Tom could have had this barrel set back, but he observed, “Lately I have had to increase powder charge to maintain 2,950 fps muzzle velocity. So to set it back would have only increased that problem. [And] I had a brand new 30″ Krieger all ready to screw on. I figured it was unlikely I’d get another full season on the old barrel, so I took it off.”
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While many of us now favor digital photography over “old-fashioned” 35mm film, don’t toss those old 35mm film canisters, especially the clear Fuji-type with secure snap-in lids. Small plastic film canisters have a multitude of uses for the shooter and reloader.
Here Are Things You Can Do with Plastic Film Canisters:
1. If you weigh powder charges after throwing them with a manual powder dispenser, throw the charges first into a film canister and then use that to drop the powder into the measuring pan on your scale. The canister will catch every kernel of powder. If you throw charges directly into a weighing pan, powder can sometimes bounce out. Using the film canister will help keep spilled powder off your loading bench and floor.
2. Store extra sets of foam ear-plugs in the canister. You never want to be without ear protection. This editor has four film canisters filled with plugs. Two go in the range kit, one goes in the car’s glove compartment, and a second stays in a lock box I use to transport pistols. This way I never find myself at the range without ear protection.
At SHOT Show 2013 we had the chance to chat with legendary barrel-maker John Kreiger of Krieger Barrels. In this wide-ranging interview, John addressed a number of questions our readers often pose…. What is better for a 6mm, 0.236″ land or 0.237″ land? What are the pros/cons of various barrel types: 3-groove, 4-groove, 6-groove, 8-groove, and 5R? What types of land/groove configurations clean up more easily? (John says the 5R might be the winner there).
John also discusses barrel cleaning and he explains why it’s unwise to pull a dirty brush back across your delicate crown: “The problem comes from the fact that abrasive materials — powder and primer residues in particular — get embedded in the brush. Essentially that is how a lap works.”
When we suggested that Krieger Barrels might want to offer three-groove barrels in the future, John surprised us by revealing that he has been considering putting a 3-groove design into production. John says that, in theory at least, a canted-land 3-groove holds a lot of promise. John hopes to build some prototype 3-grooves to test. Krieger Barrels has a 300-yard underground tunnel where barrels with various land/groove configurations and calibers can be tested using a return-to-battery fixture. John admits that tunnel testing of barrels is “on the back burner” as his company focuses on filling orders. But he says that he has a strong personal interest in testing different land/groove configurations, different amounts of choke, and different internal dimensions. We hope we’ll be able to share some results from the Krieger Barrels test tunnel in the near future.
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Forum member Rich DeSimone uses a handy “Stub Gauge” for setting shoulder “bump” and seating depth. The gauge is made from a section of barrel lopped off when the muzzle is crowned. The chambering reamer is run in about 1/4 of the way, enough to capture the neck and shoulder area of the case. Rich then uses his full-length die to “bump” a master case with the ideal amount of headspace for easy feeding and extraction. He takes that case and sets it in this Stub Gauge, and measures from the front of the gauge to the rim. He can then quickly compare any fired case to a his “master” case with optimal headspace. Since the gauge measures off the shoulder datum, this tells him how much to bump his fired brass.
In addition, the Stub Gauge can be used to set bullet seating-depth. Rich has a channel cut transversely on one side of the gauge, exposing the throat area. Since the interior of the gauge is identical to the chamber in his gun, this lets him see where a seated bullet engages the rifling. He can tinker with bullet seating length until he gets just the right amount of land contact on the bullet, confirmed visually. Then he measures the case OAL and sets his seating dies accordingly. This is much handier than using a Stoney Point Tool to measure distance to the lands. As your barrel’s throat wears, you may seat your bullets out further to “chase the lands”, but the gauge provides a constant land engagement point, in the barrel’s “as new” condition. By measuring the difference between the land contact point on the gauge and the actual contact point on your barrel, you can determine throat “migration”.
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It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.
To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author uses a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.
For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”
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OK, 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.
Readers who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into mutiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 100 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.
Complete Precision Case Prep. Jake Gottfredson covers the complete case prep process, including brass weight sorting, case trimming, primer pocket uniforming, neck-sizing, and, case-neck turning.