Tuner- advice please.

[1911WB]

Got a new DW PM7 (1911) in 10mm- need help with fixing some FTF & FTE issues with it. The first 50 rounds went perfectly. Since then I've had 5 FTF's & 3 FTE's in 150 rounds. Rounds fired include Fed. Hydra Shok; Win. 180 TC; and my 165 TC, 5.1 grns. 700x handloads (1.25 oal). I'm not too concerned about the FTF's cause I think they're magazine related (DW Mec Gar's), and I have a Metalform on order to try. But the FTE's are a different matter- the fired case is sitting in the chamber so that the next round can't feed. BTW when this occurs, the next round has extreme bullet setback (I'm crimping to about .419). The chamber and feed ramp were polished by the factory, and the chamber seems mouth seems free of sharp edges. Extractor tension checks out fine. I'm also thinking of trying an 18.5# recoil spring in place of the factory one which I believe is 20#. I'm shooting mostly target velocity rounds so far. Any other thoughts?

 

[1911Tuner]

FTExtract

Almost gotta be the extractor. Low tension...Shallow hook...Hook geometry out of spec...Worn hook...Other things to look for are rough or tool-marked chamber. And look closely at the forward area, just back of the shoulder. I've seen a tool mark there that was hard to see that was just deep enough to hang onto the case. Out of round or even barrel-shaped chamber. Most of these things are pretty rare though...98% of the time, it's the extractor.

The high-pressure cartridges tend to make extractor's function more critical.

 

[HSMITH]

40's and 10's need a LOT more extractor pressure than a 45, a LOT more.

Back that crimp off to .421-.422" and you will actually have more resistance to setback than at .419". The brass of the case springs back out and the bullet does not when you crimp, so you are actually reducing case tension with that much crimp. Just roll the mouth of the case flat against the bullet, that is as good as it will get.

 

[1911WB]

Thanks for advice

Thanks, Tuner and HSmith; I'll try deepening the extractor hook's "cup" and backing off the crimp a little. Also, the new recoil spring and Metalform mag may help. Will do a follow-up report when I get a chance. WB

 

[1911Tuner]

Deep Cup

When you make it deeper, you'll reduce the amount of tension on the rim...and you may also have to reduce the front pad a little
to move the extractor hook closer to the breechface to regain it. Do one thing at a time, and go at it slow and easy. Check to make sure the extractor nose isn't hitting the forward angle of the case extractor groove.