Open Gun Spring weight

[TMC]

Hi all, I'm looking for a fix for a problem that just started.  I just had my Para based open gun plated by Tripp Research.  The gun looks great now but won't cycle everytime.  

The failures have been shot stroking meaning the empty case will sometimes end up back in the chamber, or it will stove pipe,  or the round being stripped and chambered will get hung up half way in.

The thing ran fine before being plated.  The last time I shot it was in early November.  Specs. are Dawson Comp, Caspin slide lightened, and a 10# spring.  Shooting 124's in 39TJ brass with 8.4 of 4756.  I tried an 11# spring but that made it worse.  I didn't have a 9# to try today so that's on my list next time out.  

I'm wondering if I have a combination of factors working aginst me.  It is much colder now than in Nov., the plating could have tightened things up a bit but if it did I can't feel it.  Could the colder weather be affecting the load? I'm running the really light oil.  I remember from another thread about using heaviery springs in lighter slides but when I did that it got worse.  Any ideas?

(Edited by TMC at 5:02 pm on Jan. 10, 2002)

[38supPat]

Probably just needs to be shot in a bit more, plating does add thickness...try hand cycling it a bit at home before going shooting..then fire some thru it and see if it loosens up at all.

Pat

[ErikW]

I got lucky with my hard chromed guns and frames; they worked, but then they weren't Open guns.

Just keep shooting the thing. Might it not hurt to leave the rails unlubed for this new break-in period? What about lapping the frame and slide?

[2alpha]

DON'T RUN IT DRY, you need to keep all the lube on it you can while it breaks in. Funny thing about hard chrome is that untill it gets burnished in it is a little bit sticky. Once it's broken in it gets very slick in the high stress areas. You'll just have to baby it until it starts working, just keep shooting and oiling it and shooting and oiling. It would probably help to put a lighter spring in to get it going.  As a last resort you could use some very fine lapping compound but I doubt you'll need it.

JJ

[charles]

There is a section about this very problem on tripps web page.  Maybe something said there has been over looked.   http://www.trippresearch.com

[40 SW OpenGun]

>(Won't cycle everytime with) a 10# spring.... I tried an 11# spring but that made it worse.  I didn't have a 9# to try today so that's on my list next time out...

I think you went the wrong way moving up to a 11 lb spring from a 10 lb.  Short stroking and stovepipes implies that the slide is not cycling to the back fast enough, or far enough to get the case to smack the ejector and eject,  which means you need and lighter recoil spring (or a hotter load).  Try the 9 lb spring, but, yes, the 11 lb should make it worse.