Riflescopes are mechanical contraptions. One of the sad realities about precision shooting is that, sooner or later, you will experience a scope failure. If you’re lucky it won’t happen in the middle of a National-level competition. And hopefully the failure will be dramatic and unmistakable so you won’t spend months trying to isolate the issue. Unfortunately, scope problems can be erratic or hard to diagnose. You may find yourself with unexplained flyers or a slight degradation of accuracy and you won’t know how to diagnose the problem. And when a 1/8th-MOA-click scope starts failing, it may be hard to recognize the fault immediately, because the POI change may be slight.
How to Diagnose Scope Problems
When you see your groups open up, there’s a very good chance this is due to poor wind-reading, or other “driver error”. But my experience showed me that sometimes scopes do go bad. When your accuracy degrades without any other reasonable explanation, the cause of the problem may well be your optics. Here are some of the “symptoms” of scope troubles:
1. Large shot-to-shot variance in Point of Impact with known accurate loads.
2. Uneven tracking (either vertical or horizontal).
3. Change of Point of Impact does not correspond to click inputs.
4. Inability to zero in reasonable number of shots.
5. Unexpected changes in elevation click values (compared to previous known distance come-ups).
6. Visible shift in reticle from center of view.
7. Changed “feel” or resistance when clicking; or uneven click-to-click “feel”.
8. Inability to set parallax to achieve sharpness.
9. Turrets or other controls feel wobbly or loose.
10. Internal scope components rattle when gun is moved.
Even expensive scopes can fail, or start to perform erratically — and that can happen without warning, or for no apparent reason. Here are some signs that you may be having scope issues.
1. Click count has changed significantly from established zero at known range.
2. Noticeably different click “feel” as you rotate turrets, or turrets feel wobbly.
3. Inability to set Adjustable Objective or side focus to get sharp target image.
4. Shot Point of Impact is completely different than click value after elevation/windage change. For example, when you dial 2 MOA “up” but you observe a 6 MOA rise in POI.
When An Expensive Scope Goes Bad — Crazy Vertical Case Study
A few seasons back, this editor had a major-brand 8-25x50mm scope go bad. How did I know I had a problem? Well the first sign was a wild “drop-down” flyer at a 600-yard match. After shooting a two-target relay, I took a look at my targets. My first 5-shot group had five shots, fairly well centered, in about 2.2″. Pretty good. Everything was operating fine. Then I looked at the second target. My eye was drawn to four shots, all centered in the 10 Ring, measuring about 2.4″. But then I saw the fifth shot. It was a good 18″ low, straight down from the X. And I really mean straight down — if you drew a plumb line down from the center of the X, it would pass almost through the fifth shot.
Is My Scope Actually Malfunctioning or Is This Driver Error?
That was disconcerting, but since I had never had any trouble with this scope before, I assumed it was a load problem (too little powder?), or simple driver error (maybe I flinched or yanked the trigger?). Accordingly, I didn’t do anything about the scope, figuring the problem was me or the load.
Problems Reappear — Huge POI Swings Affirm This Scope is Toast
But, at the next range session, things went downhill fast. In three shots, I did manage to get on steel at 600, with my normal come-up for that distance. Everything seemed fine. So then I switched to paper. We had a buddy in the pits with a walkie-talkie and he radioed that he couldn’t see any bullet holes in the paper after five shots. My spotter said he thought the bullets were impacting in the dirt, just below the paper. OK, I thought, we’ll add 3 MOA up (12 clicks), and that should raise POI 18″ and I should be on paper, near center. That didn’t work — now the bullets were impacting in the berm ABOVE the target frame. The POI had changed over 48″ (8 MOA). (And no I didn’t click too far — I clicked slowly, counting each click out loud as I adjusted the elevation.) OK, to compensate now I took off 8 clicks which should be 2 MOA or 12″. No joy. The POI dropped about 24″ (4 MOA) and the POI also moved moved 18″ right, to the edge of the target.
For the next 20 shots, we kept “chasing center” trying to get the gun zeroed at 600 yards. We never did. After burning a lot of ammo, we gave up. Before stowing the gun for the trip home, I dialed back to my 100-yard zero, which is my normal practice (it’s 47 clicks down from 600-yard zero). I immediately noticed that the “feel” of the elevation knob didn’t seem right. Even though I was pretty much in the center of my elevation (I have a +20 MOA scope mount), the clicks felt really tight — as they do when you’re at the very limit of travel. There was a lot of resistance in the clicks and they didn’t seem to move the right amount.
And it seemed that I’d have four or five clicks that were “bunched up” with a lot of resistance, and then the next click would have almost no resistance and seem to jump. It’s hard to describe, but it was like winding a spring that erratically moved from tight to very loose.
At this point I announced to my shooting buddies: “I think the scope has taken a dump.” I let one buddy work the elevation knob a bit. “That feels weird,” he said: “the clicks aren’t consistent… first it doesn’t want to move, then the clicks jump too easily.”
Convinced that I had a real problem, the scope was packed up and shipped to the manufacturer. So, was I hallucinating? Was my problem really just driver error? I’ve heard plenty of stories about guys who sent scopes in for repair, only to receive their optics back with a terse note saying: “Scope passed inspection and function test 100%. No repairs needed”. So, was my scope really FUBAR? You bet it was. When the scope came back from the factory, the Repair Record stated that nearly all the internal mechanicals had been replaced or fixed:
Source of Problem Unknown, but I Have a Theory
Although my scope came with a slightly canted reticle from the factory, it had otherwise functioned without a hitch for many years. I was able to go back and forth between 100-yard zero and 600-yard zero with perfect repeatability for over five years. I had confidence in that scope. Why did it fail when it did? My theory is side-loading on the turrets. I used to carry the gun in a thick soft case. I recently switched to an aluminum-sided hard case that has pretty dense egg-crate foam inside. I noticed it took some effort to close the case, though it was more than big enough, width-wise, to hold the gun. My thinking is that the foam wasn’t compressing enough, resulting in a side-load on the windage turret when the case was clamped shut. This is just my best guess; it may not be the real source of the problem. Remember, as I explained in the beginning of this story, sometimes scopes — just like any mechanical system — simply stop working for no apparent reason.
The last half-inch or so of your barrel is absolutely critical. Any damage (or abnormal wear) near the crown will cause a significant drop-off in accuracy. Here are ways you can check the end of your barrel, using a common Q-Tip.
Use Q-Tip for Barrel Inspection
To find out if you have a burr or damage to your crown, you can use an ordinary Q-tip cotton swab. Check the edges of the crown by pulling the Q-tip gently out past the edge of the crown. If you have a burr, it will “grab” the cotton and leave strands behind.
Larry Willis has another way to use a Q-Tip: “Here’s a neat trick that will surprise you with how well it works.” Just insert a Q-Tip into your barrel (like the picture below), and it will reflect enough light so that you can get a real good look at the last half inch of rifling and the crown of your barrel. In most cases you’ll find that this works much better than a flashlight. Larry tells us: “I’ve used this method about a jillion times. Q-Tips are handy to keep in your cleaning supplies anyway. This is a good way to judge approximately how well you are cleaning your barrel when you’re at the range. It’s also the best way to examine your barrel when you’re in the field.”
This article comes from the Criterion Barrels website. It provides good, conservative advice about barrel cleaning. Understand that cleaning methods may need to be adapted to fit the amount and type of fouling (and the particular barrel). In general, we do try to minimize brushing, and we follow the procedures Criterion recommends respecting the crown/muzzle. We have also had very good success using wet patches followed by Wipe-Out bore foam. Along with the practices outlined by Criterion below, you may want to try Wipe-Out foam. Just be sure to use a fitted cleaning rod bore guide, to keep foam out of the action recesses and trigger assembly.
The above video shows how to apply Wipe-Out or other bore-cleaning foam. We use a slightly different method. First, we use 3-4 wet patches to remove loose carbon fouling. Then we apply the foam as shown, but usually from the muzzle end (with bore guide in chamber). Here’s the important point — after 20-30 minutes, once the bubbles have dissipated, we apply the foam a second time, getting more of the active ingredients into the barrel. We then patch out, as shown, after 3-4 hours.
What is the Best Way to Clean a Rifle Barrel?
We are asked this question quite frequently alongside requests for recommended break-in procedures. Improper barrel cleaning methods can damage or destroy a barrel, leading to diminished accuracy or even cause a catastrophic failure. When it comes to barrel maintenance, there are a number of useful techniques that we have not listed. Some techniques may work better with different barrel types. This series of recommendations is designed to incorporate a number of methods that the Criterion Barrels staff has used successfully both in the shop and on their personal rifles. Please feel free to to list your own recommendations in the below comments section.
We recommend the use of the following components during rifle cleaning:
• Cloth patches (sized for the appropriate caliber)
• Brass jag sized properly for your bore
• One-piece coated cleaning rod
• General bore cleaner/solvent (Example: Hoppes #9)
• Copper solvent of your choosing (Example: Sweets/KG 12)
• Fitted cleaning rod bore guide
• Plastic AP brush or toothbrush
• Q-Tips
• Plastic dental picks
• CLP or rust preventative type cleaner
There are a number of schools of thought relating to the frequency in which a barrel should be cleaned. At minimum we recommend cleaning a barrel after each shooting session to remove condensation, copper, and carbon build-up. Condensation is the greatest immediate threat, as it can cause the barrel to rust while the rifle sits in storage. Copper and carbon build-up may negatively impact future barrel performance, increasing the possibility of a failure in feed or function. Fouling should be removed whenever possible.
The below tips will help limit the wear of different parts of your barrel during routine maintenance, helping extend the life of the barrel and improving its performance.
The Lands and Grooves
This portion of the barrel may experience reduced efficiency due to copper fouling and cleaning rod damage. If copper fouling takes place during the initial break-in of the rifle, make sure to check our barrel break-in article.
For regular maintenance we suggest using a single piece coated cleaning rod rather than the traditional segmented rod or bore snake. While segmented rods and bore snakes may be convenient for field use, the corners between the segments may bow out and catch on the lands, scraping along the length of the rifling. Residual grit and particles from expended cartridges may also get caught between segments, resulting in an abrasive surface working its way down the length of the barrel. Most bore snakes will remove significant amounts of carbon fouling, but may fall short in the removal residual carbon buildup and copper fouling during deep cleaning. Good rods can be sourced from multiple manufacturers, but we have found good results using both Pro-Shot and Dewey brand products.
General cleaning requires the use of patches rather than nylon or brass bore brushes. Brass brushes may be required when aggressive cleaning is required, but can lead to unnecessary wear on the barrel if used frequently. This is not due to the nature of the soft brushes themselves, but from the abrasive particles of grit that become embedded in the material that is being run repeatedly through the bore. We recommend the use of bore guides when cleaning from both the muzzle and breech. These bore guides will help serve to protect the crown and throat from cleaning rod damage.
If significant resistance develops while running the cleaning rod through the bore, no attempt should be made to force it in further. Back the rod out and inspect the barrel to determine the cause of the resistance. The jag may be pushing between a bore obstruction and the rifling, digging a divot into the barrel before pushing the obstruction back through the muzzle. One way to minimize the risk of a stuck rod is by utilizing a slightly smaller patch during the initial push.
The process of cleaning the length of the rifling is relatively straightforward:
1. Check to make sure the rifle is safely unloaded.
2. Carry out any necessary disassembly procedures prior to cleaning.
3. Remove bolt (if possible) and insert fitted cleaning rod bore guide in action.
4. Soak a patch in bore solvent (similar to Hoppes #9).
5. Center and affix the patch on the brass jag, inserting it into the chamber end of the barrel. A misaligned patch may cause the jag to damage the lands of the rifling, so make sure the patch is centered on the jag.
6. Run the patch the full length of the barrel, retracting it upon reaching the end of the muzzle.
7. Let the solvent sit for a minute.
8. Continue to run patches through the bore until carbon residue is minimized.
9. Run a dry patch through the bore to ensure carbon residue has been removed.
10. Soak a patch in copper solvent (Sweet’s or KG-12).
11. Run the patch through the bore, leaving it to sit for 3-5 minutes (do not let solvent sit for more than 15 minutes.*)
12. Repeat this process until no blue residue remains on the patches.
13. Run a patch of Hoppes #9 and a dry patch through the bore to neutralize the copper solvent.
14. Inspect the barrel prior to reassembling the rifle, verifying that no bore obstructions remain.
*Please note that some ammonia-based copper solvents may prove to be corrosive if left sitting in the barrel for an extended period of time. It is essential that these solvents be removed within 15 minutes to avoid ruining the bore.
The Crown
The crown is the portion of the barrel where the bullet loses contact with the lands and grooves and proceeds to exit the firearm. The area most critical to accuracy potential is the angle where the bullet last touches the bore of the barrel.
Avoid damage to this area by using a plastic toothbrush and CLP type cleaner to scrub the crown from the exterior of the barrel. Even the most minimal variation in wear to the crown will negatively impact barrel performance, so be careful to avoid nicking or wearing away this part of the barrel.
A while back, the Precision Rifle Blog conducted a fascinating study of Muzzle Brakes. PRB figured out a way to show the actual “blast pattern” of gasses ejecting from the ports of muzzle brakes. The result was a fascinating (and eye-catching) series of images revealing the distinctive gas outflows of 20+ different types of muzzle brakes. If you are considering buying and installing a muzzle brake on your rifle, you should definitely review this important PRB Muzzle Brake Test.
For a prone shooter, particularly on dusty, dirty or sandy ground, muzzle blast is a major bummer. Muzzle blast can be very disturbing — not just for the trigger-puller but for persons on either side of the gun as well. Some muzzle brakes send a huge shockwave back towards the shooter, and others send blast towards the ground, kicking dirt and debris into the prone shooter’s face. If there was a way to illustrate those factors — shockwave and debris — that might help shooters select one brake design over another.
Cal Zant at PrecisionRifleBlog.com applied a unique blend of creativity and resourcefulness to try to answer that question for 20+ muzzle brakes. Using high-speed photography and household products, he captured the blast pattern of 20+ different brake designs for easy side-by-side comparison. Can you figure out how Cal managed to show muzzle brake blasts so clearly? His “hi-viz” solution, revealed in the article, is very clever. See the eye-opening results for 20+ brakes, with illustrative photos, by visiting the Precision Rifle Blog Muzzle Brake Ground Signature Test Page.
Click Map to launch interactive webpage with info for all 50 states.
Going hunting soon? Need to find out about hunting licenses, deer tags, local regulations, and the best hunting areas? Then visit WheretoHunt.org. This website has an interactive map of the country. Simply click on a state to find the info you need.
For all 50 states, the NSSF provides information about hunting licenses and permits, where to hunt, hunter education classes, laws and regulations and more. For each state you’ll also find a link for required applications and license forms. Have a safe and productive hunt this year.
NRA publication Shooting Sports USA (SSUSA) has thousands of articles online, all free for the reading. Many of these stories have been written by top competitors, including National and Olympic Champions. You will find SSUSA articles spotlighted every week on the NRA Competitive Shooting Facebook page. We recommend you bookmark that page as a valuable resource. Here are four notable SSUSA articles that have been featured on Facebook this month. Go to SSUSA.org to see even more current articles, with new content every day.
Here is an insightful, fairly lengthy 1850-word article about the phenomenon we call mirage. The article explains how and why mirage appears, how it can best be monitored, and how mirage can indicate both wind velocity and direction. Top competitors follow the adage “Mirage is your friend”, because mirage can often be the most important indicator of wind variables — sometimes even more important than wind flags. “The mirage is more sensitive than the flags since it has less inertia and momentum”, wrote Desmond T. Burke, in his book, Canadian Bisley Shooting, an Art and a Science.
Well worth reading, this SSUSA article talks about the properties of mirage. Here is a sample:
“Mirage — can make all the difference between a shot landing squarely in the X-ring or being victimized by an undetected downrange breeze. The true power of mirage is found in its ability to betray the subtlest of breezes downrange. Its fluid movement… can not only provide wind direction, but speed as well.
Typically, the ability to detect mirage is maximized on warm, sunny and sultry days. Expect mirage to be most pronounced in mid-morning or early afternoon, although it ignores these rules with regularity[.]
Mirage is extremely powerful at identifying winds of less than 12 mph, particularly those gentle breezes subtle enough to not even bother moving the flags.
When there is no wind, or a gentle head or tail wind, mirage will appear to be ‘bubbling’ directly up from the ground. Many call this ‘boiling’, and it is probably the easiest of all to detect.
As a general rule of thumb, when wind speed increases, overall height of the waves produced by the mirage is reduced. Large peaks and valleys in the waves mean that particular mirage is being driven by a very slight breeze. Conversely, crest size is reduced with wind speed, making it harder and harder to detect, until the mirage disappears entirely at somewhere around 12 miles per hour. In other words, the taller mirage’s waves appear, the slower the breeze.”
Authored by the late Glen Zediker, this article covers barrel break-in procedures. It is particularly useful for dealing with factory barrels. We CAUTION readers — with outstanding, hand-lapped custom barrels from top barrel-makers, you may want to do very little break-in — clean sparingly and keep barrel heat low. Do NOT use abrasives aggressively. On our Krieger and Brux barrels, we simply wet-patched every 2-3 rounds for 20 rounds and the barrels shot superbly from the start with minimal fouling. But for factory barrels, a moderate break-in process may prove beneficial.
Zediker explains: “Lesser, lower-cost barrels are going to have more pronounced … imperfections within the bore[.] These imperfections are largely tool marks resulting from the drilling and rifling processes. And if it’s a semi-automatic, like an AR-15, there might be a burr where the gas port was drilled. The goal of break-in is to knock down these imperfections, thereby smoothing the interior surface.”
As one who has experienced a cartridge case-head blow-out with a 9mm pistol, this Editor is very conscious of the risks involved and the damage a blow-out can do to the pistol, to the magazine, and (worst of all) to the shooter. Even with new brass, the possibility of a case failure is always present. And even if the case remains intact, we’ve seen primer failures that create a dangerous jet back towards the pistol shooter. That’s why shooters should always employ protective eyewear whenever they shoot.
We love our wheelguns, but there’s no doubt that forcing cone damage can occur, particularly with hot loads and if your cylinder-to-barrel gap is excessive. This article explains how to inspect your revolvers, and how to mitigate the likelihood of forcing cone damage. The article also explains how to clean your revolvers properly. This is very important to avoid build-up of lead and powder residues.
Sometimes you’ll get a barrel that doesn’t stabilize bullets the way you’d anticipate, based on the stated (or presumed) twist rate. A barrel might have 1:10″ stamped on the side but it is, in truth, a 1:10.5″ twist or even a 1:9.5″. Cut-rifled barrels, such as Kriegers and Bartleins, normally hold very true to the specified twist rate. With buttoned barrels, due to the nature of the rifling process, there’s a greater chance of a small variation in twist rate. And yes, factory barrels can be slightly out of spec as well.
After buying a new barrel, you should determine the true twist rate BEFORE you start load development. You don’t want to invest in a large supply of expensive bullets only to find that that won’t stabilize because your “8 twist” barrel is really a 1:8.5″. Sinclair International provides a simple procedure for determining the actual twist rate of your barrel.
Sinclair’s Simple Twist Rate Measurement Method
If are unsure of the twist rate of the barrel, you can measure it yourself in a couple of minutes. You need a good cleaning rod with a rotating handle and a jag with a fairly tight fitting patch. Utilize a rod guide if you are accessing the barrel through the breech or a muzzle guide if you are going to come in from the muzzle end. Make sure the rod rotates freely in the handle under load. Start the patch into the barrel for a few inches and then stop. Put a piece of tape at the back of the rod by the handle (like a flag) or mark the rod in some way. Measure how much of the rod is still protruding from the rod guide. You can either measure from the rod guide or muzzle guide back to the flag or to a spot on the handle. Next, continue to push the rod in until the mark or tape flag has made one complete revolution. Re-measure the amount of rod that is left sticking out of the barrel. Use the same reference marks as you did on the first measurement. Next, subtract this measurement from the first measurement. This number is the twist rate. For example, if the rod has 24 inches remaining at the start and 16 inches remain after making one revolution, you have 8 inches of travel, thus a 1:8″-twist barrel.
Determining Barrel Twist Rate Empirically
Twist rate is defined as the distance in inches of barrel that the rifling takes to make one complete revolution. An example would be a 1:10″ twist rate. A 1:10″ barrel has rifling that makes one complete revolution in 10 inches of barrel length. Rifle manufacturers usually publish twist rates for their standard rifle offerings and custom barrels are always ordered by caliber, contour, and twist rate. If you are having a custom barrel chambered you can ask the gunsmith to mark the barrel with the twist rate.
Our take on Bore-Store Gun sleeves is simple: They work great, so buy them and use them — for ALL your valuable firearms.
Winter’s here, with rain and snow in much of the country. We known readers will have their guns in the safe for long periods. For winter storage, we recommend Bore-Stores. These thick, synthetic-fleece sacks cushion your guns, preventing nicks and scratches. The breathable fabric wicks away moisture, and the fibers are coating with corrosion inhibitors. I personally use Bore-Stores for in-safe storage with all my guns, and I have never had one of my guns rust inside a Bore-Store, even when I lived a stone’s throw from the ocean and its salty air.
Bore-Stores are offered in a range of sizes to fit everything from a snub-nosed revolver to a 33″-barrelled Black Powder Rifle. Bore-Stores can be purchased for $9.99 – $28.99 from Borestores.com. For most scoped rifles, we recommend the 10″x46″ SCR-1 case ($25.99). The Bore-Store manufacturer, Big Spring Enterprises will also craft custom sizes on request. For a long-barreled F-Class or ELR rig you may need a custom length. Or you can remove the scope and use the 7″x52″ SG-1 Shotgun Bore-Store for up to 32″ barrel ($28.99).
API-Brand Anti-Rust VCI Storage Bags — Affordable and Effective
Consider VCI Bags for Long-Term Storage
While we prefer Bore-Stores for regularly-used guns, if you have heirloom firearms that will be kept in storage for very long periods without seeing any use, you may want to grease them up and place them in the thin, but rugged API brand VCI Storage Bags. The interior VCI lining emits a safe corrosion inhibitor vapor. The multi-layer exterior locks out humidity and airborne contaminants. These bags are also resistant to petroleum-based chemicals and seal out moisture. They have a handy velcro opening.
Here’s one VITAL bit of advice for using sealed gun storage bags. Be absolutely sure, before you seal up the bags, that your guns are DRY and that all metal surfaces have been coated with an effective anti-corrosive, such as BoeShield T9 or Eezox. NOTE: If you can’t afford the $15 API sacks, Brownells offers a three-pack of 12″x 60″ anti-rust rifle sacks for $22.99 — under 8 bucks a gun. That’s certainly cheap insurance for rifles and shotguns that may cost many thousands of dollars.
Get Your Guns Out of Foam-lined Cases — They Are Rust Magnets
Just about the worst thing you can do for long-term storage (short of leaving your rifle outside in the rain) is to store firearms in tight, foam-padded cases. The foam in these cases actually collects and retains moisture from the air, acting as the perfect breeding ground for rust. Even in warm summer months, humid air can leave moisture in the foam.
Remember, those plastic-shelled cases with foam interiors are for transport, not for long-term storage. Don’t repeat the mistake of a wealthy gun collector I know. He stored four valuable Colt Single Action Army (SAA) revolvers in individual foam-padded cases, and locked these away in his gun safe. A year later, every one of his precious SAAs had rusted, some badly.
Product innovation is all about “building a better mousetrap”, or in this case, building a better bore-cleaning patch. A real smart guy, Shane Smith, has invented a triangular patch that earned a patent. The U.S. Patent Office has awarded a utility patent for BoreSmith’s triangular Pyramid Patch™. This unique cleaning patch was designed by Shane Smith, a mathematician/physicist who employed his scientific and firearms knowledge to create innovative bore-cleaning products.
BoreSmith’s clever Triangle Patch™ (aka Pyramid Patch) presents more cleaning surface area to the bore wall than does a conventional square or round patch (of equivalent size). At the same time, the unique geometry makes Triangle Patches much less likely to jam in the barrel. This is because the notches in the sides of the triangle allow the patch to sit more uniformly on the jag (without bunching up). In addition, the Pyramid patch is must less likely to jam due to pleating. One reason conventional patches get stuck is unwanted 5-layer pleating. The special notches in the Pyramid patch remove all or most 5-layer pleating. As a result the patch does not bunch up and this also reduces rod bowing.
Triangle Patch Function and Geometry Explained (See 1:18 time-mark):
NOTE: Despite what you may see in this video, you should ALWAYS insert brushes and patches from the chamber end first, using a fitted cleaning rod bore guide. With bolt-action rifles, NEVER insert a cleaning rod (with brush or jag) in through the muzzle. This may damage the delicate crown of your barrel.
A few years back, Our friend Grant Guess had a “close encounter” with a bad primer. An apparently defective primer caused part of the casehead on one of his rounds to blow out. This, in turn, allowed high pressure gas to vent through the damaged primer pocket. Take a good look, boys and girls. This is yet another very good reason to wear safety glasses … EVERY time you shoot. The cartridge was a 6.5-06, handloaded in necked-down Winchester-headstamp .270 Win brass. Grant reports:
“I had a blow-through between the primer and the primer pocket today. The action was really smoking and I got a face full of gas. This was a reasonably light charge. Thank God for safety glasses.
I should also mention that it appears there is a 3/64 hole that is halfway between the primer and the primer pocket. Like it burned a small jet hole through both of them.”
Could this happen to you? It just might. On seeing this damaged case, one of Grant’s Facebook friends, Chris D., observed: “Search the internet, you will see a lot of these pin hole ‘in the corner’ failures. Obviously Winchester has some issues with the LR primers.”
Careful Examination Reveals Apparent Primer Defect
After this incident, Grant examined the damaged case: “I [measured] the flash hole and it is not over-sized or under-sized. The primer clearly has an area where it had a defect. At [50,000 CUP], it doesn’t take much of a defect to cause issues. There was a slight bit of pucker-factor on the next shot….”
For the next 20 shots, we kept “chasing center” trying to get the gun zeroed at 600 yards. We never did. After burning a lot of ammo, we gave up. Before stowing the gun for the trip home, I dialed back to my 100-yard zero, which is my normal practice (it’s 47 clicks down from 600-yard zero). I immediately noticed that the “feel” of the elevation knob didn’t seem right. Even though I was pretty much in the center of my elevation (I have a +20 MOA scope mount), the clicks felt really tight — as they do when you’re at the very limit of travel. There was a lot of resistance in the clicks and they didn’t seem to move the right amount.
The last half-inch or so of your barrel is absolutely critical. Any damage (or abnormal wear) near the crown will cause a significant drop-off in accuracy. Here are ways you can check the end of your barrel, using a common Q-Tip.
Sometimes you’ll get a barrel that doesn’t stabilize bullets the way you’d anticipate, based on the stated (or presumed) twist rate. A barrel might have 1:10″ stamped on the side but it is, in truth, a 1:10.5″ twist or even a 1:9.5″. Cut-rifled barrels, such as Kriegers and Bartleins, normally hold very true to the specified twist rate. With buttoned barrels, due to the nature of the rifling process, there’s a greater chance of a small variation in twist rate. And yes, factory barrels can be slightly out of spec as well.
Here’s one VITAL bit of advice for using sealed gun storage bags. Be absolutely sure, before you seal up the bags, that your guns are DRY and that all metal surfaces have been coated with an effective anti-corrosive, such as BoeShield T9 or Eezox. NOTE: If you can’t afford the $15 API sacks, Brownells offers a three-pack of 
Remember, those plastic-shelled cases with foam interiors are for transport, not for long-term storage. Don’t repeat the mistake of a wealthy gun collector I know. He stored four valuable Colt Single Action Army (SAA) revolvers in individual foam-padded cases, and locked these away in his gun safe. A year later, every one of his precious SAAs had rusted, some badly.
