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545X39 AR upper

2K views 18 replies 6 participants last post by  4thIDvet 
#1 ·
My 5.45X39 AR barrel closes on the no go gauge.. it a Criterian barrel.. I'll see if I can shoot it like it is but I don't like that BS. US makers can't make this stuff right.. :censored2 B2B
 
#2 ·
Does it just close with feel? or does it swallow the guage? I'd send it back if it was new. There was a thread from a year or two ago or so where someone was saying some manufacturer was using different specs on 5.45 bolts. Can't remember who it was though. Kreiger owns Criterian or something to that effect. Give then a shout Criterion Barrels, Inc.
 
#3 ·
It closes with a little resistance..but very little.. the problem is I got the barrel from a guy on a board at a good deal it was new...not used..and I got the bolt from Model 1 sales at not a good deal..so I really can't return anything..and I can't play musical bolts with the 5.45 as the head dia and firing pins are different.. I'm using AK-builders gauges.. I guess I have to run it and see if it works.. I wonder if others have upper that close on the no go gauges also.. B2B
 
#4 ·
ok im gonna play stupid and ask here......

why cant you adjust the headspace?

if it has a lip on it you can always turn it down a little.
 
#5 ·
Adjusting the headspace on a AR rifle requires the barrel extension to be removed and a thread set back, and it really cant be done once the gas port is drilled because it will no longer time up top dead center... it requires a lot of tools and expertise... I don't have either and unless it is short chambered and a reamer could be run into it, but it's not it is long.. It may be a bolt issue..but I really can't test it on a round using a 556 bolt because of the head dia difference.. If it is a bolt issue, I may be able to get model 1 sales to swap me a different bolt but that is going to be a majoy PITA and I already had to have them send me a firimg pin that was all F't up.. I'll just run it and see if it functions but I think I may be FKd another issue with excessive hadspace is the extractor doesn't grab the rim of the case.. I tried a case and it didn't grab the loaded wolf round.. that is why I checked HS.. I'll contact Kreger.. and see what's the deal.. B2B
 
#8 · (Edited)
I almost wonder if they sent you the wrong bolt. I recently opened up a 556 bolt to .398" for a 9mm build. The 9mm bolts I measured had a bolt face diameter between .397" to .405" with the 5.45x39 bolt being towards the lower end of that spread. I was going to just use the 5.45 bolt until I found used 556 bolts cheap. Whats the bolt face diameter of yours?
 
#16 ·
Sounds like he has a 5.45x39 upper, but made brass from 222 cases which have the same rim as a 223/556 at .378". That would explain why his extractor may not be grabbing the case well. Since he is reloading, the excessive headspace can be compensated for. Years ago I had a well worn M1 with excessive headspace. I simply sized the brass until it would just close the bolt and used those rounds only in that gun. Heck they wouldn't even chamber in any of my 30-06 guns (I tried because I was curious).
 
#18 ·
head space closed with a no go gauge, on my barrel bolt combo.. the Head space can not be determined with a case.. it can not head space with a ammo..brand. ammo either fits or doest fit.. if it doesn't fit headspace is too short..if it fits it still may not be correct headspace.. with excessive headspace.. the weapon may or may not fire, it may or may not separate cases, it may or may not blow out primers or misfire w/ light firing pin strikes etc.. unless you have a gauge you can not know for sure if it is correctly headspaced.. if your headspace is off.. the rim may not engage the extractor correctly.. that error is/was with a factory steel case wolf not 222 reformed cases.. My reformed case extract better than the wolf ammo... everything is new unfired,, so it may just be /need some break in.. But the head space is loose..according to a 545X39 gauge.. B2B
 
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