The reason why the P7M8 & P7M13 have differing ammo reliability issues

I'll be honest, I've never shot +P+ with any of my P7M8s. It jams? That would be a first for me.

benderx4 said:

I'll be honest, I've never shot +P+ with any of my P7M8s. It jams? That would be a first for me.

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on the p7m8 the nose of the 127 grain ranger SXT +p+ can jam into the 2 red circled areas while feeding into the chamber. The +p+ aspect of the previous round may help 'direct' the next round to feed into those two areas. However, it only jams because the hollowpoint can snag into those two red circled areas; a round nose FMJ or a hollowpoint with a smoother nose are much less likely to hang up in those areas.

My understanding is that the P7M13 does theoretically feed more reliably than a P7M8, although I personally have never had any issue with the P7M8.

I must admit my P7's all see only Winchester Bulk Whitebox 9mm FMJ. If I ever start carrying one, I will look into how they work with SXT's.

Would polishing the feedramp help?

The P7 has an usupported chamber? Does that mean it has a predisposition to KB??

JPG

It's not an unsupported chamber in the sense of a Glock.

jpgeorge said:

I must admit my P7's all see only Winchester Bulk Whitebox 9mm FMJ. If I ever start carrying one, I will look into how they work with SXT's.

Would polishing the feedramp help?

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A polish would probably help things. But opening up the chamber ramp just a tad more (but not nearly as much as on the M13) followed by a polish would fix the problem.

jpgeorge said:

The P7 has an usupported chamber? Does that mean it has a predisposition to KB??

JPG

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Yes they had to cut the chamber ramp back quite a bit because of how high on the feed ramp the bullet tip hits (see the copper marks circled in red on the M13 photo). I have never heard of a KB! in the P7M13 related to this issue, but I believe the unsupported nature of the chamber is one of the reasons why very high pressure rounds can jam tight in the chamber of some M13's. They jam so tight that the brass has to beat out of the chamber with a dowl and hammer. What is interesting is that two identical appearing M13's can share the same box of +P+ and one will work perfectly and the other will have every spent round jammed tight in the chamber.

tktm said:

on the p7m8 the nose of the 127 grain ranger SXT +p+ can jam into the 2 red circled areas while feeding into the chamber.

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This is the specific cartridge I use in my "carry" pistols... one of which used to be an M8. Now its a heeler. I have fired several hundred rounds of this ammunition through two M8s and two heelers, without the first hint of any sort of difficulty/malfunction.

While your particular pistol might have issues with this ammunition, where do you get the idea that ALL of them do????

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LSP 972 said:

This is the specific cartridge I use in my "carry" pistols... one of which used to be an M8. Now its a heeler. I have fired several hundred rounds of this ammunition through two M8s and two heelers, without the first hint of any sort of difficulty/malfunction.

While your particular pistol might have issues with this ammunition, where do you get the idea that ALL of them do????

.

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I never said that ALL of them do, what I pointed out is where it does jam on a P7M8.
Whether or not the version of 127 grn SXT you use in your pistol will jam in your gun, in your hand depends on more factors that I have accounted for in this post. But one thing you can be assured of is that there are two places on the P7M8 that can snag a bullet and that the P7M13 does not have those two places.

I will have to get a few more boxes of 9mm SXT's to see if there are any problems with my P7's. I will probably never carry the M13, but it would be good to know.

Does the 9mm SXT in a P7 reach as high a chamber pressure as a 40S&W SXT does in my USP40F?

JPG