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Posted: 12/29/2006 9:26:30 AM EDT
I finished a Yugo M70AB2 slabsided build yesterday on a NDS-M92 receiver. This kit had a perfect barrel and 95% finish on the metal. After a trying build, i.e. MIGing additional material on the mag release to stop the mag from floping around, having to shorten the lower forearm wood .20 thousandths, replacing a long rear trunion rivet; I ran into the problem of the carrier not wanting to close all the way. Now, this is a matching numbers kit, so it was headspaced at the factory. I removed the bolt which let the carrier slide into place. I swapped bolts and carriers to no avail. I checked the length of the ejector which was .015 longer than a NDS-4 receiver. The bolt seems to be tight against the front trunion after the carrier stops. Looking at a functional Yugo, the bolt is still loose after the carrier group is locked up with no bullet in the chamber. I think I am looking at a headspace problem. What do you builders think????
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The bolt will not close at all, so I can't check the headspace. Yes, I assumed that the kit was headspaced at the factory correctly.
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If the bolt will not close at all then you need to adjust your headspace. |
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barrel in to far(headspace)....i had a romy kit like that...looks as if the barrel pin was drilled the first time not headspaced so they pressed it out and redrilled from the factory that way most will be correct going right back together but sometimes there are problems even w/ matching # kits so u got to check them! |
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your headspace would have to be way way off for this to be a headspace prob so much that i would look in other places first so start with checking the feed ramp (make shure its in correct and not loose) then look for burs or crud in the trunnion let us know if you find anythang there PS on most the standard trunnion yugos ive seen 1/2 the parts dont have #'s so its kinda hard to tell if its a matching kit or not |
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I did some closer checking: The feedramp is not loose, it is in tight & matches the rails. The trunion is clean with no burrs or crud. Using another rifle, the bolt closes easily, the bolt wiggles freely, and the carrier finishes closing not affecting the bolt. On the affected rifle, the bolt contacts the face of the barrel and everythind stops, the bolt is tight against the barrel and can go no where else. The serial # on the receiver ( there were no numbers on the trunion) matched all the numbers on the rest of the kit. I am going to remove the barrel pin and try to press the barrel out a small amount to see if this will allow the bolt to close. Then I will have to get a set of gauges to safely check /set the correct headspace. Thanks for all the help with this problem. I will repost when I finish! 
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He does say that the bolt face hits the barrel and stops. Does that not sound like a barrel sitting WAY too far in? |
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Update; The barrel is pressed in too far by several/many thousandths of an inch. By pressing the barrel back out, the bolt & carrier closes as a normal operation. I still need to properly headspace this build before redrilling the barrel pin. I am relived to know that I didn't screw up the build.....
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