P7 PSP and WWB 115 gr. FMJ

[wmssims]

I have been shooting WWB 115 gr. FMJ out of my P7 PSP. I always use the scraper tool to clean out the gas piston cylinder before beginning my shooting (in addition to the usual cleaning). The P7 PSP fires just fine for about 50 rounds, but thereafter the slide will not stay back after a mag is emptied, and it gets harder and harder to rack the slide and load a round from a loaded mag. Problem goes away if I strip the gun and scrape out the cylinder and begin shooting again. Of course, the gun is pretty hot by then, so I have to wait for cool-down before stripping.

My question is whether this is typical, in your experience, or if you can think of another reason why I am having this problem after only 50 or so rounds.

wmssims

[Geohans]

Over many years, this has happened to me with particular brands of ammo-- others not. Mine was never so severe that the slide would not lock back; gun always functioned perfectly, just got sticky around 100 rounds.

I don't recall having a problem w/ WWB. After a thorough cleaning, try some Federal.

your situation is definitely an extreme version of a not-unheard-of problem; ask at the 'cult' for more experiences/solutions.

[ripley16]

The piston cylinder should only need scraping after say 500 rounds or more. That should not, nor need not be a routine part of cleaning. I am wondering if you are leaving some liquid in the cylinder, either cleaner or oil. The cylinder should be dry, and the piston may have a very light coat of lube.

You may in fact be over lubing the entire pistol. It requires very little to operate properly. I say this because after shooting about 700 rounds of WWB in my P7, I took the scraper to the cylinder expecting much crud. There was very little. Routine swabbing, say with a Q-tip and Hoppes should keep your cylinder spotless. That and keep it dry.

[wmssims]

Thanks very much for the suggestions. I'll try it first with the WWB but with little or no lubricant, after putting a part of a patch into the cylinder to make sure there is no fluid of any kind in there.

wmssims