We are re-publishing this article at the request of Forum members who found the information very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can be dangerous, potentially causing serious injury.
On the highly-respected Riflemans’ Journal blog, created by our late, dear friend German Salazar*, there was an excellent article about Cartridge Case-Head Separation. In this important article, Salazar (aka GS Arizona) examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.
The photo below shows a case sectioned so that you can see where the case wall becomes thinner near the web. You can see a little arrow into the soot inside the case pointing to the thinned area. This case hadn’t split yet, but it most likely would do so after one or two more firings.
Paper Clip Hack for Detecting Problems
The article provided a great, easy tip for detecting potential problems. You can use a bent paper clip to detect potential case wall problems. Slide the paper clip inside your case to check for thin spots. GS Arizona explains: “This simple little tool (bent paper clip) will let you check the inside of cases before you reload them. The thin spot will be immediately apparent as you run the clip up the inside of the case. If you’re seeing a shiny line on the outside and the clip is really hitting a thin spot inside, it’s time to retire the case. If you do this every time you reload, on at least 15% of your cases, you’ll develop a good feel for what the thin spot feels like and how it gets worse as the case is reloaded more times. And if you’re loading the night before a match and feel pressured for time — don’t skip this step!”
* Sadly, German Salazar passed away unexpectedly on June 21, 2022 at age 62. German was a great inspiration to this site who helped guide the creation of the AccurateShooter Forum. A brilliant man, expert attorney, and top-tier marksman, German will be sorely missed in the shooting sports world.
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.
Forum 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.
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”.
Have you recently purchased a new scope? Then you should verify the actual click value of the turrets before you use the optic in competition (or on a long-range hunt). While a scope may have listed click values of 1/4-MOA, 1/8-MOA or 0.1 Mils, the reality may be slightly different. Many scopes have actual click values that are slightly higher or lower than the value claimed by the manufacturer. The small variance adds up when you click through a wide range of elevation.
In this video, Bryan Litz of Applied Ballistics shows how to verify your true click values using a “Tall Target Test”. The idea is to start at the bottom end of a vertical line, and then click up 30 MOA or so. Multiply the number of clicked MOA by 1.047 to get the claimed value in inches. For example, at 100 yards, 30 MOA is exactly 31.41 inches. Then measure the difference in your actual point of impact. If, for example, your point of impact is 33 inches, then you are getting more than the stated MOA with each click (assuming the target is positioned at exactly 100 yards).
How to Perform the Tall Target Test
The objective of the tall target test is to insure that your scope is giving you the proper amount of adjustment. For example, when you dial 30 MOA, are you really getting 30 MOA, or are you getting 28.5 or 31.2 MOA? The only way to be sure is to verify, don’t take it for granted! Knowing your scopes true click values insures that you can accurately apply a ballistic solution. In fact, many perceived inaccuracies of long range ballistics solutions are actually caused by the scopes not applying the intended adjustment. In order to verify your scope’s true movement and calculate a correction factor, follow the steps in the Tall Target Worksheet. This worksheet takes you thru the ‘calibration process’ including measuring true range to target and actual POI shift for a given scope adjustment. The goal is to calculate a correction factor that you can apply to a ballistic solution which accounts for the tracking error of your scope. For example, if you find your scope moves 7% more than it should, then you have to apply 7% less than the ballistic solution calls for to hit your target.
NOTE: When doing this test, don’t go for the maximum possible elevation. You don’t want to max out the elevation knob, running it to the top stop. Bryan Litz explains: “It’s good to avoid the extremes of adjustment when doing the tall target test.I don’t know how much different the clicks would be at the edges, but they’re not the same.”
Should You Perform a WIDE Target Test Too?
What about testing your windage clicks the same way, with a WIDE target test? Bryan Litz says that’s not really necessary: “The wide target test isn’t as important for a couple reasons. First, you typically don’t dial nearly as much wind as you do elevation. Second, your dialed windage is a guess to begin with; a moving average that’s different for every shot. Whereas you stand to gain a lot by nailing vertical down to the click, the same is not true of windage. If there’s a 5% error in your scope’s windage tracking, you’d never know it.”
Verifying Scope Level With Tall Target Test
Bryan says: “While setting up your Tall Target Test, you should also verify that your scope level is mounted and aligned properly. This is critical to insuring that you’ll have a long range horizontal zero when you dial on a bunch of elevation for long range shots. This is a requirement for all kinds of long range shooting. Without a properly-mounted scope level (verified on a Tall Target), you really can’t guarantee your horizontal zero at long range.”
NOTE: For ‘known-distance’ competition, this is the only mandatory part of the tall target test, since slight variations in elevation click-values are not that important once you’re centered “on target” at a known distance.
A Virginia Congressman has introduced legislation which will take suppressors (aka “silencers”) off the NFA list and make them much easier to purchase. That’s a good idea because a quality suppressor can reduce firearm sound levels by 30 decibels (dB) or more. U.S. Rep. Ben Cline’s Hearing Protection Act (H.R. 404) would remove firearm suppressors from the list of restricted items under the 1934 National Firearms Act (NFA). That would reduce costly licensing ($200 per suppressor) and burdensome background checks. Instead, suppressors would be regulated under the 1968 Gun Control Act (GCA) with the same type of background check done with retail firearm purchases. The legislation would also amend statutory suppressor definitions.
Under current law, an individual purchasing a suppressor must locate a regulated NFA Class III retailer, complete a Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) Form 4 with the model and serial number of the suppressor, and obtain two passport photos and fingerprint cards from a local police department. The local chief law enforcement official must receive a completed copy of the application. Then the form, photographs, and fingerprints must be sent to ATF along with a check to pay the $200 tax. The customer can obtain the suppressor from the NFA Class III retailer upon an additional background check through FBI’s National Instant Criminal Background Check System (NICS).
Congressman Cline’s legislation would eliminate those requirements and make suppressors available with the same type of paperwork and background check required for a firearm. H.R. 404 would also clarify the definition of suppressors, ensuring that components like mounts, baffles and end caps are not erroneously classified as standalone suppressors or “silencers”.
“Congressman Cline’s Hearing Protection Act will have the federal government recognize firearm suppressors for what they are. These are accessories to a firearm that make recreational shooting and hunting a safer experience”, said Lawrence G. Keane, NSSF Senior V.P. and General Counsel. “These safety devices reduce the report of a firearm to a level that won’t cause instant and permanent hearing damage.” There are currently 2.6 million legally owned suppressors in the United States.
See Through Suppressor in Super Slow Motion (110,000 fps) — Click Arrow to Watch:
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.
Firearm suppressors (aka “silencers”) reduce the report of a firearm from a level roughly equal to that of a jet taking off which causes instant and permanent hearing loss to one that is safe, but still equal to a jackhammer. That decibel level will not permanently damage hearing. Suppressors work similar to a car’s muffler, redirecting exhaust gases.
Our friend Dennis Santiago was doing some dry firing practice recently, using a SCATT sensing device. This electro-optical unit shows a trace of barrel/muzzle movement on a computer screen, allowing a shooter to improve his hold and aiming. With practice, you get steadier, and learn to break the shot more perfectly. Top position shooters worldwide use this system. Dennis tells us: “This is my dry fire practice set up. I’m working on my approaches to the target today. You need the SCATT’s traces to see the feedback of what’s going on.” Here is one trace from Santiago’s morning training session:
Dennis trains indoors at his house: “The set-up is in a room with the target about 15 feet away mounted on a scope stand at eye height and aligned. This morning, it’s focus and trigger control. My offhand form is gonna get there bit by bit. There are many details to turn into instincts.”
SCATT MX-02 Training System
The SCATT MX-02 is an electronic shooter training system that is capable of operating outdoors with live, centerfire ammunition, at distances from 25 yards to 600 yards. Tony Chow tested this product for AccurateShooter.com. As fitted to his AR-15 Service Rifle, Tony concludes this is a very useful tool that can help High Power competitors refine their technique and shoot higher scores. FULL REVIEW HERE.
How the SCATT MX-02 Works
The SCATT sensor mounted on the end of the barrel has a digital camera that recognizes 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. By sensing the exact moment of shot release, the SCATT can also interpolate relative shot placement (for a single shot or series of shots) — but this is not the same as an electronic target which actually records the exact shot impact location on the target.
Pro shooter Kirsten Joy Weiss demonstrates the SCATT MX-02 electronic training system:
The system traces and records valuable information such as hold pattern, shot hold duration, follow-through, recoil pattern, and much more. The latest SCATT MX-02 systems can be used both indoors and outdoors up to 300 meters (and possibly more). READ FULL SCATT MX-02 TEST HERE.
SCATT traces reveal muzzle movements during the aiming process.
This barrel’s shoulder was 0.025″ off the action because Red Locktite had been used on the threads.
Gunsmith Thomas ‘Speedy’ Gonzales offered this interesting report about how NOT to headspace a barrel. Hopefully you never discover something like this…
“A good friend and customer sent this rig in for repair after FedEx damaged the rifle during inbound transport from another smith. After repairing the stock and rebedding it, I decided to re-polish the barrel to make the repair perfect. Well this just added insult to injury as the barrel did not want to come off. After a few choice words, the barrel finally broke free only to reveal something very disturbing. It seems the barrel had been ‘headspaced’ by using RED Loctite to hold it in place.” [Editor: That’s definitely NOT how barrels should be fitted.]
Speedy was not happy: “I hope the smith that did this sees the photos and realized what jeopardy he put my customer in or anyone who shot the rifle for that matter. When cleaned up, the shoulder on the barrel was over 0.0250″ (25 thousandths) away from the face of the receiver.” [Editor: That’s a lot in this business]. Check out the images below to see how much the barrel rotated further inward when cleaned up. The barrel spun in nearly another eighth-turn or more. Not good.
This thought-provoking article is one of the 15 most popular Daily Bulletin features over the last 12 months. We are republishing this story today for readers who may have missed it the first time around…
Here’s a little known fact that may startle most readers, even experienced gunsmiths: your barrel wears out in a matter of seconds. The useful life of a typical match barrel, in terms of actual bullet-in-barrel time, is only a few seconds. How can that be, you ask? Well you need to look at the actual time that bullets spend traveling through the bore during the barrel’s useful life. (Hint: it’s not very long).
Bullet-Time-in-Barrel Calculations
If a bullet flies at 3000 fps, it will pass through a 24″ (two-foot) barrel in 1/1500th of a second. If you have a useful barrel life of 3000 rounds, that would translate to just two seconds of actual bullet-in-barrel operating time.
Ah, but it’s not that simple. Your bullet starts at zero velocity and then accelerates as it passes through the bore, so the projectile’s average velocity is not the same as the 3000 fps muzzle velocity. So how long does a centerfire bullet (with 3000 fps MV) typically stay in the bore? The answer is about .002 seconds. This number was calculated by Varmint Al, who is a really smart engineer dude who worked at the Lawrence Livermore Laboratory, a government think tank that develops neutron bombs, fusion reactors and other simple stuff.
On his Barrel Tuner page, Varmint Al figured out that the amount of time a bullet spends in a barrel during firing is under .002 seconds. Al writes: “The approximate time that it takes a 3300 fps muzzle velocity bullet to exit the barrel, assuming a constant acceleration, is 0.0011 seconds. Actual exit times would be longer since the bullet is not under constant acceleration.”
We’ll use the .002 number for our calculations here, knowing that the exact number depends on barrel length and muzzle velocity. But .002 is a good average that errs, if anything, on the side of more barrel operating life rather than less.
So, if a bullet spends .002 seconds in the barrel during each shot, and you get 3000 rounds of accurate barrel life, how much actual firing time does the barrel deliver before it loses accuracy? That’s simple math: 3000 x .002 seconds = 6 seconds.
Gone in Six Seconds. Want to Cry Now?
Six seconds. That’s how long your barrel actually functions (in terms of bullet-in-barrel shot time) before it “goes south”. Yes, we know some barrels last longer than 3000 rounds. On the other hand, plenty of .243 Win and 6.5-284 barrels lose accuracy in 1500 rounds or less. If your barrel loses accuracy at the 1500-round mark, then it only worked for three seconds! Of course, if you are shooting a “long-lived” .308 Win that goes 5000 rounds before losing accuracy, then you get a whopping TEN seconds of barrel life. Anyway you look at it, a rifle barrel has very little longevity, when you consider actual firing time.
People already lament the high cost of replacing barrels. Now that you know how short-lived barrels really are, you can complain even louder. Of course our analysis does give you even more of an excuse to buy a nice new Bartlein, Krieger, Shilen etc. barrel for that fine rifle of yours.
You may have heard the phrase “blueprinting an action”, but do you know what that really means? Do you know what operations are done to an action during the blueprinting process? To help you understand, gunsmith Bill Marr of RifleShooter.com has created a helpful article showing a Rem 700 blueprinting job start to finish. This article spotlights how the procedures can be done with manual tools. Bill, who runs 782 Custom Gunworks Ltd., can also perform many of these operations with modern automated machinery. In fact, Bill has written a follow-up article on Truing a Rem 700 receiver with a Lathe.
Bill explains: “Blue-printing, or truing a rifle action, ensures the receiver face, threads, lugs, bolt lugs, and bolt face are square to the center line of the receiver.” In Bill’s informative article, Bill shows how he blueprints a Remington 700 short action receiver with .308 Win bolt face. He covers the following procedures step by step:
Action Disassembly
Ream Minor Diameter of Receiver Threads
Square the Receiver Lugs
Square the Face of the Receiver
Lap the Bolt Lugs
Square the Bolt Face
Bill employed a variety of tools from Brownells to complete the blueprinting job, including: Remington 700 Armorer’s Kit; Manson Receiver Accurizing Kit; Bolt Lapping Kit; Bolt Face Truing Tool; Manson Receiver Ring Facing Cutter; Multi-Vise with Jaw Pads; Silicone Carbide Abrasive; and Do-Drill Cutting Oil.
Highlights from the Rifleshooter.com article:
1. Chasing the Threads
We use the bushings to guide the receiver tap. This chases the threads and ensures they are square.
2. Truing the Receiver Face
Using the receiver facing tool, the front of the receiver is trued. The tool is placed over the tap and turned by hand. We used Do Drill to lubricate it.
3. Lapping the Lugs
The bolt lapping tool screws into the front of the action and applies rearward pressure on the bolt face. A little bit of lapping compound is placed on the front of the receiver lugs. The bolt handle is then raised and lowered repeatedly. Note — it is critical that we do not get any lapping compound on any other surfaces.
4. Truing the Bolt Face
On this bolt, the central part of the bolt face was low. After the truing operation, this Rem 700 bolt face is now completely square to the action.
IMPORTANT: Rifleshooter.com states: “This article highlights our project and is presented for information purposes only. This provides an overview of the process and should not be attempted without the guidance and supervision of an experienced gunsmith“.
Bryan Litz and The Science of Accuracy Academy delivered a notable Podcast with vital information for all handloaders. This Podcast examines the effects of humidity variances on powder. Bryan notes: “If you want to know how much this can matter, we’re talking up to 200 fps difference for the same load of H4350 in 6.5 Creedmoor” at opposite extremes of humidity.
Bryan adds that “Most shooters don’t realize what a big deal this can be — it overshadows many of our efforts to make consistent velocity and hit targets. This can happen in loaded rounds not just for hand loading where you expose powder to ambient humidity. This is especially important for hunters considering the range of environments hunting ammo goes through.”
CLICK the above graphic to access first half of Podcast for free.
BONUS — Four More Science of Accuracy Podcasts
Here are four more of our favorite Podcasts from Bryan Litz’s Science of Accuracy Academy. Click on each item to hear the first half of each podcast for free.
Want More? Subscribe to The Science of Accuracy Academy
If you’d like to benefit from hearing ALL the full-length Science of Accuracy Academy Podcasts you can get a subscription to the Academy for just $9.95 per month. This grants you access to all Podcasts, exclusive videos, learning resources, and bullet data sheets.
The Where To Shoot Mobile App quickly locates shooting ranges near you, drawing on North America’s most comprehensive directory of shooting ranges. Users can search by current location, state, or zip code. Once you locate a range, you can view activities offered along with a summary of range facilities. You can even get driving directions. If you don’t want to install an App, you can also access the NSSF shooting range database and maps via the NSSF Where-to-Shoot webpage.
The app is modeled after NSSF’s popular WhereToShoot.org® website and is updated frequently with range information for every U.S. state and Canadian province. Once you’ve located a place to shoot, the App can provide directions to the range. The App also includes video tips for shooters, news, and firearm-safety information.
On the highly-respected Riflemans’ Journal blog, created by our late, dear friend German Salazar*, there was an excellent article about Cartridge Case-Head Separation. In this important article, Salazar (aka GS Arizona) examined the causes of this serious problem and explained the ways you can inspect your brass to minimize the risk of a case-head separation. As cases get fired multiple times and then resized during reloading, the cases can stretch. Typically, there is a point in the lower section of the case where the case-walls thin out. This is your “danger zone” and you need to watch for tell-tale signs of weakening.
Forum 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.”
Verifying Scope Level With Tall Target Test
Gone in Six Seconds. Want to Cry Now?
