Doh! Make Sure Your Ammo Fits Your Chamber!
If you don’t match your ammo to your chamber, bad things can happen, that’s for sure. A while back, Forum member BigBlack had an experience at the gun range that reminds us of the importance of safety when shooting. He encountered evidence that someone had fired the wrong cartridge in a 7mm WSM rifle. The problem is more common than you may think. This Editor has personally seen novices try to shoot 9mm ammo in 40sw pistols. BigBlack’s story is along those lines, though the results were much more dramatic. It’s too bad a knowledgeable shooter was not nearby to “intervene” before this fellow chambered the wrong ammo.
7mm-08 is Not the Same as a 7mm WSM
BigBlack writes: “I know this has probably been replayed a thousand times but I feel we can never be reminded enough about safety. This weekend at the range I found a ruptured case on the ground. My immediate thoughts were that it was a hot load, but the neck area was begging for me to take a closer look, so I did. I took home the exploded case and rummaged through my old cases until I found a close match. From my investigative work it appears someone shot a 7mm-08 in a 7mm WSM. Take a look. In the above photo I’ve put together a 7mm WSM case (top), the ruptured case (middle), and a 7mm-08 case (bottom).”
The photo reveals what probably happened to the 7mm-08 case. The shoulder moved forward to match the 7mm WSM profile. The sidewalls of the case expanded outward in the much larger 7mm WSM chamber until they lacked the strength to contain the charge, and then the case sides ruptured catastrophically. A blow-out of this kind can be very dangerous, as the expanding gasses may not be completely contained within the action.
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It’s even worse when cops make those mistakes. Our club hosts half a dozen small PDs for their training and we all descend on the place when they are done to police brass (which they steadfastly refuse to police themselves, so..). Plenty of 9MM’s shot in 40s&w and even a couple of 9’s out of .45acp’s as well which I did not think one could make happen. Scary.
One part of the problem was that the casehead wasn’t being held by the bolt, that WSM case head is a lot bigger than a .308; look how far the case is deformed up from the base.
Ha – that’s an ‘improved’ case and then some! I once managed to get a 223 Rem to chamber and fire in a 6.8SPC rifle – no pressure of course with the seriously undersize bullet, but it still managed to produce a magnificently swollen-body case with some small splits. It made me a lot more careful afterwards about checking ammo box labels before loading.
I found an odd-looking 9 x 21 case on my usual range.
I didn’t know they made a “belted” version……….
Faint signs of chamber flutes; maybe one of our “lads” tried to run some through one of their MP-5s?
They have .40 cal Glocks, but, as far as I know they still use 9 x 19 MP-5s.