Finally got a chance to test the newest version of Winchester's 127gr +p+ RA9TA "T-series" in a P7M8. In the latest incarnation of this round, the hollow point is wider and shallower than previous version. Basically I was looking to see if the design changes improved reliability in P7M8's as compared to the older version where I encountered a Failure to Feed Jams approximately every two hundred rounds. see
I had hoped that the hollow point profile change might reduce the jamming likelihood against the sides of the barrel/chamber.
The test involved 2 different shooters and 2 different P7M8's (each shooter shot both guns).
The "T-series" ammo induced a previously unseen failures in both guns with both shooters.
The issues were as follows.
(1) Failure to feed with breech face crushing the side of the cartridge against the chamber (last round)
(2) Failure to lock back slide
Of the 150 rounds fired, only 1 magazines worth (8 rounds) ran without a stoppage.
In an effort to remedy the issue, the magazine springs were replaced at approximately the 80 round mark with new +10% wolf springs.
It was after the change over to the Wolff mag springs when we finally had a total of 1 magazines without a failure to feed.
The shooting was done over 3 different trips to the range.
Additionally we fired 124gr +p Ranger Q4362 with ZERO malfunctions, and also had ZERO malfunctions with a hot custom loaded 100gr +p+ round (much greater recoil than the other rounds fired).
It is possible that increasing the recoil spring weight might reduce the proclivity of the new 127 grain to fail in the manner we described. However it would seem that the current loading of the RA9TA "T-series" has a sweet spot for failure in P7M8's, hence it is probably best avoided.
We also noted a slight reduction in accuracy and precision in the new T-series as opposed to the original "Black Bullet" SXT loading of the round.
The photos below show the "T-series" fired at a silhouette from a standing position at 25 yards, and the last round FTF jam in the gun after new mag springs had been installed. With the new springs the jam location changed slightly, there was less crushing of the side wall of the cartridge.