Example of Over Pressure Signs

[AccelR8]

Sometimes reloaders like me wonder what actual pressure signs look like. I always stay within published load data and therefore don’t see any of the classically described pressure signs, or if I do they are very subtle and maybe hard to discern. In the picture, they’re not so subtle

I was given a bucket of 5.56 and 9mm brass with a few oddballs mixed in. This 350 Legend case was in there. When I picked it up out of the bucket the first thought that came to mind was it looks like a little belted magnum.

The primer was gone. Brass had been extruded into the ejector hole, visible on the left in this picture, and into the extractor space, visible on the right. It was not possible for me to focus the entire picture so I tried for the best overall focus that shows all the features of an obviously over pressure round.

I can’t say how much the case head expanded because I obviously don’t have a before measurement but measuring the portion of the case just in front of the “belt,” the portion that was in the chamber, and comparing to the “belt” which by the way is not round, the unsupported portion of the case measures from .008” to .0115” larger.

I think this one was dangerously close to a catastrophic failure.

 

[jelenko]

Wow.
I just wonder what the story is behind it.

 

[TSFineGuns]

Back it down .2grs and call it a day

 

[dellet]

It’s also a pretty good example of being over gassed.

The extractor pulled over the rim and tore it.
The flow into the ejector looks like it also might have been twisted some and tried to shave off what had been pushed into the ejector hole.

 

[AccelR8]

The flow into the ejector looks like it also might have been twisted some and tried to shave off what had been pushed into the ejector hole.

.

 

[dellet]

.View attachment 1600314

The bolt twisted and the case was still stuck in the chamber.
Could have been in a bolt action and happened when they beat the bolt open.
Or gas gun trying to extract the case while still clinging to the chamber.

That round was certainly high pressure. But you can get similar results in a gas gun that is very over gassed, without a popped primer or blown out case head. I’ve seen case heads pulled completely off with low pressure loads.

 

[divingin]

Sometimes reloaders like me wonder what actual pressure signs look like. I always stay within published load data and therefore don’t see any of the classically described pressure signs, or if I do they are very subtle and maybe hard to discern. In the picture, they’re not so subtle

I was given a bucket of 5.56 and 9mm brass with a few oddballs mixed in. This 350 Legend case was in there. When I picked it up out of the bucket the first thought that came to mind was it looks like a little belted magnum.

The primer was gone. Brass had been extruded into the ejector hole, visible on the left in this picture, and into the extractor space, visible on the right. It was not possible for me to focus the entire picture so I tried for the best overall focus that shows all the features of an obviously over pressure round.

I can’t say how much the case head expanded because I obviously don’t have a before measurement but measuring the portion of the case just in front of the “belt,” the portion that was in the chamber, and comparing to the “belt” which by the way is not round, the unsupported portion of the case measures from .008” to .0115” larger.

I think this one was dangerously close to a catastrophic failure.

View attachment 1600309

I found several (like a half dozen) 45ACP cases that were sort of similar. Web bulged to a significant degree, primer pockets *very* enlarged, extractor groove compacted, primers (once punched out) looked like little chef's hats with the corners having flowed to the very limit of the chamfer to the head.

I was really glad I wasn't at the range when those were fired.

 

[searcher]

I found several (like a half dozen) 45ACP cases that were sort of similar. Web bulged to a significant degree, primer pockets *very* enlarged, extractor groove compacted, primers (once punched out) looked like little chef's hats with the corners having flowed to the very limit of the chamfer to the head.

I was really glad I wasn't at the range when those were fired.

That is a lot harder to do on a .45 ACP. Those MUST have been hot!

 

[tommeboy]

That 350 legend brass was a common occurrence with Win ammo on the first 2 batches of factory ammo. They put a roll crimp on the ammo when it was supposed to have a taper crimp as it head spaces off the mouth. Well the case got jammed into the throat and it blew out the primers and usually had a case separation.

Then Federal way overloaded their ammo trying to eak out that last 50fps and popped the primers.