This is frame wear that you're referring to. I'm aware of this as it has been discussed here many times. But the original post said...
"The locking abutment on the barrel and locking recess in the slide are slowly but surely shearing each other."
These are two completely different issues.
Point taken. I should have been more specific by referring to the last paragraphs of the linked material regarding the importance of precise lubrication in this pistol design:
[size=10]Let me try and describe in words - the cycle of events -
At the instant of the slide beginning rearward travel, as round fires and pressures begin to back off from peak, we have the barrel moving rearward by approx 1/4", as recoil springs are being compressed by slide - (exerting as they do said rearward force against barrel lug) - at which point the lug slot allows it to drop on the pin, and there it stays while slide continues all the way to the rear.
The slide progresses then forward, stripping a new round - which is fed into the lowered barrel and chambered, assisted by the feed ramp. The completion of the auto load is aquisition of full battery with the slide having moved fully forward, the recoil assembly is now relatively relaxed, and we see the bolt face area impinged on the round's base to complete the action.
The last 1/4" or so as around goes into battery and the slide closes, is when the lug slot then rides over the pin to lift the chamber area (barrel rear if you like) once more and go into full lock-up.
This incidentally is why that lug/pin area needs lubrication. (Emphasis added.)[/size]
Without a photograph of the wear points, I'm admittedly speculating about the cause of the problem. My first thought, however, was that the pistol may have been running a little too dry. An examination of the internals of my own R9 does not show a similar problem. I would be confident that the factory could diagnose and correct the problem JY has described and hope that he will keep us informed.
