After a pleasant morning ringing the gong with my 7.9mm’s, I found this case laying next to to all my empties. I thought it was interesting.

rim = .474
head = .470
lenghth = 2.526
shoulder= .457
mouth (outside) = .342
mouth (inside) = .303

Is this a 30/06 case that has been formed into something else?
From the looks of the primer, someone seems to have a wee bit of a pressure problem!

Just guessing, but looks like a 30-06 AI (Ackley Improved), or some varient there of.
The holed & flattened primer could be from a couple different things, Headspace could do this also, by allowing the primer to be slamed back aganst the bolt face. A over long firing pin and/or a weak firing pin spring can also pierce the primer. The case length is also a little long, which makes me lean toward a HS issue, causing a fair amount of case stretch to have taken place


Measure that shoulder angle. But from the looks of it I’d say you have yourself a plain old '06 Ackley Improved. 40 degree shoulder.

The flattened primer means more than a “wee bit of a pressure problem”. Take all the possible explanations that tailgunner gave (and the neck splits too), add them all together and it’s more of a “Here, hold my beer and watch this.”


When I said a “wee bit” I was trying to inject a little humor. I quess I should have been more obvious. Its hard to tell where the base ends and the primer begins.
Aside from that, there is another posible cause, if you fired a full load military 30/06 round in a .30 AI chamber, wouldn’t you come up with about the same results?


I knew your “wee bit” comment was a wee bit tongue-in-cheek. There is nothing wee bit about the looks of that case head. Maybe that’s why the shooter left it. Of course, knowing a few shooters like that, he probably simply lost it and was heading home to load up some more, after a beer or three.

Shooting a full power load in an improved chamber actually results in less pressure than the factory load would generate. That’s because an improved chamber has greater volume than a standard chamber so the gas would have a bigger vessel to expand in.

When fire-forming cases for an improved chamber you either use factory loads or a reload at the top end of the scale. Otherwise the case will not fully fill out, at times.