Avoid Trouble, Inspect Cartridge Brass
Photo shows 6.5 Creedmmor brass cases ruptures consistently due to malformed rifle chamber. This illustrates why it's important to inspect cartridge brass.
My last blog on ruptured 6.5 Creedmoor cases earned me much ire and condemnation. I hope it also shined a spotlight on the need to inspect cartridge brass (empty cases) fired in new rifles or even new rifle/ammo combinations. Even though guns and ammo are tightly controlled and regulated for safety and tolerances, things sometimes go wrong -- usually due to operator error, but sometimes to manufacturer error, too.I caught the most grief from readers (or should we say lookers?) who seem to have responded to the accompanying photo rather than the explanatory words. They felt I was throwing Hornady "under the bus" and giving the rifle maker a free ride because I didn't show or name it. What they missed was my main point: one should carefully examine all aspects of incidents like this before jumping to conclusions and assigning blame. Any rifle or ammo maker can let a "lemon" slip through the line from time to time. This is no reason to condemn the company and it's entire line. If we all did that we'd be riding horses instead of trucks. I can't think of one auto maker that hasn't has a major recall. (By the way, none of the rifle makers guessed by readers was the one involved in this incident.)
Inspect Cartridge Brass Before Firing
Most shooters, I fear, buy generic ammo or the brand Dad used or Charlie recommended, load their rifles and blaze away, rarely if ever examining the cartridges or the ejected, empty brass cases. One and done. The gun fired. A hole appeared on the target. What's to examine? Lots.First, read the head stamp on the end of the cartridge to make sure it matches the chambering of your rifle. Though they look similar, a 30 TC is not the same as a 308 Win. Many cartridges can fit and fire in much different chambers. A 270 Win. in a 30-06 Springfield. Probably a 7mm-08 Rem. in a 270 Win., etc. Handloaders who neck-down 30-06 Springfield or 308 Win. brass must be especially careful, since head stamps will be incorrect. If you aren't adept at discerning bullet diameter by eye, carry a caliper in your range kit and measure.
Inspect Cartridge Brass After Firing
Inspect cartridge brass immediately after firing and you'll catch ruptures like these that resulted from firing 300 Win. Mag. cartridges in a 300 Weatherby chamber.
It's easy to inspect cartridge brass when it comes out of a chamber smoking with the primer falling out. 7mm-08 fired though a 25-06 Rem. Soft bullet swaged down and made it out without exploding the barrel.
You should get in the habit of inspecting cartridge brass after its fired because its condition can tell you a lot about itself and the firearm that ignited it. A gentleman trying to get his 300 Weatherby Magnum to group reasonably well at a hunting camp learned this when we showed him his ejected brass, the shoulders split. He was shooting 300 Winchester Magnum cartridges in the 300 Weatherby chamber. He didn't realize they were different cartridges. "No wonder I've never gotten accurate groups out of this gun!" he exclaimed. Turns out he'd been shooting it like that for years.I've seen split or ruptured brass come out of 22 Long Rifles, 17 HMRs, 17 WSMs, 6mm Remingtons, and 12-gauge shotguns. Lots of 12-gauge shotguns. Those seem to be built with looser tolerances than rifles. I've seen plastic cases split, brass heads punctured and split, and heads pulled completely off the plastic hulls. Was it the shell's fault or the gun's or a bit of both? Once we were in the dove fields of Argentina without gunsmithing tools when a couple of 12 gauge autos started ripping shells apart. In the heat of the action, we just kept shooting. Probably not the smartest idea in the world, but nothing was damaged except for every 10th shell or so.That unwise approach was similar to the one we repeatedly took as kids when various hand-me-down 22 rimfires kicked out ruptured cases. No one got injured, the bullets still hit some of the jackrabbits we were targeting, and no one had money to fix the old rifles anyway. But ruptured cases are never a good thing. The cause should be determined and rectified. There are plenty of shooters extant with mangled or missing body parts because they didn't examine their fired brass and/or didn't correct the problems that caused it.
Things to Look For When You Inspect Cartridge Brass
Photo shows a cutaway view of a rifle barrel and chamber showing a cartridge in place with minimum space around it.
Photo shows 25-06 Rem. cartridges and 7mm-08 Cartridges, one of which has had the primer blown out of its pocket by excessive pressure upon firing.
Head Separation: This is when the cartridge is literally pulled apart just above the head where brass thickness tapers down. It's usually a sign of excessive head space, the distance from the closed bolt face to the datum line within the chamber that stops the cartridge's forward progress. Sometimes excessive headspace prevents the primer from igniting because the firing pin barely hits it. That's the best way to discover excessive headspace. It's cured by turning the barrel more deeply into the receiver.Just a bit of excessive headspace can show up if you full-length resize and reload cases. I had this issue with an otherwise sweet shooting Remington M788 in 6mm Remington. It had just enough extra headspace that the brass work-hardened as it stretched and got squeezed smaller with each shot/reloading. Eventually half a case stayed in the chamber while the head pulled out via the extractor. And that's when a 22-year-old, self-taught rifleman first learned the significance of headspace.Cracked Necks and Shoulders: These can result from brass that is too hard. In a brass case you want hardness at the head, but malleability at the shoulders and neck so that area expands easily to release the bullet and seal the chamber against blow-back gases. This area can also work-harden. I've had old 270 Winchester brass split while merely sitting on the shelf for many years. I'd resized and reloaded it so many times that the hardened brass gave up the ghost just while gripping the bullets. Annealing (heating and rapidly cooling) the neck and shoulder brass alleviate this, but temperature levels are critical.Blown Primers: Primers that exit the rifle with holes in them indicate excessive firing pin length and/or energy. If they are backed out from the pocket or fall out completely, you're looking at a severely oversized pocket or excessive pressure from too much powder. Flattened primers are a classic sign of too much pressure. Black carbon fouling around the primer edges indicates they are leaking from poor fit or excessive pressure or both. Cratering around the firing pin indentation also suggests too much pressure. The brass literally heats and flows around the firing pin during ignition.Ruptured or Grossly Misshapen Brass: This is usually a reflection of a bad chamber, either oversized or malformed. Chambers are reamed in barrel breeches to provide a cavity into which a specific cartridge fits with just enough room to expand easily but minimally. We're talking tolerances of .006" to as little as .001". Cartridges are built within certain tolerance ranges, too, to match standards for chambers. However, if you get a rifle with a chamber at the large end of the tolerance scale and a cartridge at the low end -- and the brass is sufficiently brittle -- you could see a case rupture. Worse would be a chamber reamed out-of-round, which is probably what happened with our recent 6.5 Creedmoor incident.
Regardless Your Ammo or Rifle, Inspect Cartridge Brass For Proper Fit and Performance
If you have tested your rifle and ammo extensively and know it intimately, there's probably no need to inspect cartridge brass at every firing -- or every few hundred firings. But changes in ammo, rifle, brass, powder, primers, bullets -- anything new -- suggest careful brass inspection. It's always a good idea.The author's handloading habit makes it certain that he'll inspect cartridge brass soon after firing -- and usually before. Except for that 7mm-08/25-06 incident when distractions got the better of him.
