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Discussion Starter #1 (Edited)
Hi there, I just bought a PSP, best I can tell, it is was made in 1979, then resold by HK as "Grade A" in 2006, and not shot since.

I really like this gun, it is everything I expected. I have put about 300 rounds through it, all factory loaded ammo. Mostly Remingtom UMC, some Speer, CCI, and Federal. I collect the brass, and I've noticed that all the brass fired in the PSP has a distinct bulge in it. Sort of like a "Glock bulge", but all the way around.

I wasn't able to take a good picture of it, but it can easily be felt:





The bulge is right where that last carbon ring is towards the base of the case.

Is this normal for the PSP? Something to worry about?


Thanks for your help,

Rheingold
 

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Rheingold:

It is not uncommon to see what you describe as a "bulge" on soft brass ammo in a fluted chamber. The series of shallow grooves in the chamber of the P7 and other HK's can allow such a bulge to occur around the case IF the brass is slightly soft or thin (and/or the pressure is excessive) or both. The brass slightly "flows" (opens) into the flutes all around the case resembling the bulge you describe. Often cheaper ammo types save money by using poorer quality brass. It can also be hard on the extractor having to pul the case free but the P7 will eject even w/o an extractor in place due to the operting principle. Of greater concern is the crack in the case visible in your photo. I would not use that amo type again in any HK fluted chamber. My guess is it was the Rem. UMC
G3Kurz
 

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Discussion Starter #4 (Edited)
Thanks for the replies. The first picture was indeed UMC. I have noticed that stuff burns very dirty.

Here's an example of better ammo, Winchester Ranger Law Enforcement Frangible non toxic 90gr +P (Q4346). This stuff burns so clean, even the inside of a spent case is bright and shiny, no carbon at all. And since it is +P rated, I'm assuming better quality brass. On this picture you can see how the brass was fire formed to the chamber. No flowing into the flutes at all, but right where the chamber imprint ends 3/4 down the case, the bulging ring all the way around the case:





Does the P7 chamber not fully support the case? Do I have a defective gun?
 

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p7 suggested bullet weight is 100 to 124gr. +p is higher pressure and is probably contributing the bulging.
 

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Discussion Starter #6
p7 suggested bullet weight is 100 to 124gr. +p is higher pressure and is probably contributing the bulging.
There was no difference in the bulging between four different brands of ammo, from 90gr to 124gr, +P or not. All cases look the same.
 
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