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View Full Version : PSL headspacing...any words from the wise?


Malikovski
June 22, 2007, 12:22
I am building a PSL from one of the recent Centerfire kits, with a matching recevier with trunnions installed from the same source.

Pressing the barrel back in took some wecsoggery, but was accomplished with a standard 12 ton press:

http://www.adamanttech.com/guns/wecsog.jpg

Yes, that is a dirt wall in the background. Really adds to the "Pakistani cave" feeling of the workshop.

But here's the problem, I can't check headspace. Apparently, unlike bolt guns in 7.62x54R, the PSL headspaces off the shoulder rather than the rim. I learned this the hard way by tapping the barrel in and out, and wondering why the bolt would either not close on any gauge, or close on both GO and NO GO.

After a couple sweaty hours in this hopeless pursuit, I got out the calipers and measured the bolt and the rim gauges I had, and the recess for the rim is indeed deeper than even the NO GO gauge. The bolt face touches the chamber before the rim gauge can contact it.

I know of no where I can buy 7.62x54R headspace gauges for the PSL. The rim gauges are useless.

So I stripped the bolt and used a catridge as a GO gauge. Bolt closed on this. I added a 0.008" shim cut from a set of feeler gauges to the cartridge base as a NO GO, and the bolt would not close for any money.

Since this is a matching number parts kit and the barrel is set in the position it came from the "factory", so to speak, I would normally not be too concerned.

However, with the barrel so positioned and pinned, the bolt requires some pressure to close. Not a lot, but if you just slide the carrier forward it will hang up at the point at which the top lug on the bolt has to go "around the corner" in it's track in the bolt carrier, and requires a shove with the thumb at the back of the carrier to close fully.

The whole thing was very tight (carrier fit to rails, and so on), so is this just new parts that need to break in with some shooting, or should I be concerned?

If I am reading the signs right, it seems that the headspace is set as tight as it could be, since any tighter and the bolt will not rotate into the locking lugs, even when empty. I'd be inclined to put a hundred rounds through it and see if that helps, except that doing so involves putting my face next to an explosive and hoping for the best.

I've lubed it up and worked the action back and forth by hand, which has helped considerably, but it's still tighter than I'd like.

Anyone with experience with PSL headspace care to weigh in?

Virginia Jake
August 20, 2007, 13:42
Dang! Your work space is only slightly more organized than mine!

Sorry, but I don't know anything about PSL's!

Yours,
Virginia Jake

Malikovski
August 20, 2007, 13:52
I've cleaned it up a bit since.

Finally found a gunsmith familiar with PSLs to advise me, and it turned out headsapce was fine. I had the wrong grand of gauges initially and some other complications.

It test fired very well, and in fact seemed softer shooting than my AKs. They are available (completely assembled) from several sources now. I recommend picking one up if you're interested in AK-pattern rifles.

nihonsei84
August 21, 2007, 03:09
http://i127.photobucket.com/albums/p138/nihonsei84/pakistan55.jpg?t=1187681281

Pakistani Gun Factories... often immitated, never duplicated. :beer:

I've recently got a PSL parts kit from AKParts and am now awaiting the matching receiver with trunnion. It'll be interesting to see if I run into the same issues that you have. Over at Weaponeer panaceabeachbum (of thompson machine (www.thompsonmachine.net/gun.htm) fame) used the ol' masking tape on the case shoulder to headspace his PSL builds. You might try using a little bit of lapping compound to smooth out the action... just a thought. Good luck with your build and let us know how it shoots! :beer: :beer: