AR Sponsor
Posted: 8/26/2013 1:19:33 PM EDT
|
So I've built a JD Machine lower wth a PSA lower kit and finally received my PSA M4 - 16'' CMV CL Upper with Bolt and BCG. Unfortunately it was short stroking so I figured it just needed a break-in so after 2 trips, tear downs/cleanings and about 150 rounds (one round at a time is always fun) it was still short stroking. It should mention that it was failing to hold open on the last shot too. I tried the usual ammo. switch and used 3 different gens of PMAGs all to no avail. Gas keys were tight so before I went looking into the gas tube/block I figured I'd switch out my Stag lower in the PSA upper and low and behold everything ran perfectly.
So I felt I had an issue with the lower (i.e. bolt catch, mag seating depth, etc....) but as a test I put the alleged malfunctioning lower on my stag upper and it worked perfectly. I thought that maybe the "Bug" worked itself out so I reunited it with the new PSA upper but it went back to short stroking and not holding open. So I either just keep my AR's mismatched since they are now both completely functional all switched out or try and figure out this out. Am I missing something blatantly obvious? |
|
what kind of upper do you run on the stag? carbine? midlength? m16 or ar15 bcg? does the bolt have an o-ring under the extractor on both or just one? I would weight the buffers too - it's most likely an issue with the buffer and/or the different weights from ar15 (stag bcg) and the m16 (psa bcg) bolt carrier groups |
AR Sponsor