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Posted: 9/20/2004 1:31:29 AM EDT
I had a bolt break on me at the range this weekend. The lugs on both sides of the extractor broke off.
I have personal knowledge of this happening 3 other times to people I know with a 762X39 upper. Do any of you know what causes this and is there any way of correcting the problem? Thanks for your replies.
Link Posted: 9/20/2004 8:51:26 AM EDT
Problem would be incorrect heat treating/finishing. Sounds like you all got bolts from the same batch.

Best bet would be to find a new supplier that would have a different batch of bolts, and may not that the brittle defect.
Link Posted: 9/20/2004 11:33:30 AM EDT
Link Posted: 9/20/2004 1:49:09 PM EDT
Could also be a bad barrel. I kept blowing extractors on mine until I found out the bolt would not close on a go gauge.

Changed barrels and problem solved.

Link Posted: 9/21/2004 5:50:36 AM EDT
Hiya Plate -
Check your headspace, I had a 5.56 AR that broke two, come to find out the bolt closed on a NOGO guage. The barrel extension was cocked on the barrel, and the bolt lugs were not all engaging the lugs in the barrel extension. It is either this, or the bolts are improperly hardened. Ops
Link Posted: 9/21/2004 2:52:54 PM EDT
Link Posted: 9/22/2004 2:35:46 AM EDT
[Last Edit: 9/22/2004 2:36:17 AM EDT by plateshooter]
Thanks for your replies, I sent the bolt back to the supplier who told me it has a lifetime warranty. If I get another failure, I will send the upper back. I don't have any headspace gauges for 762X39, so I will let them check it if need be. I don't know if there is much pressure difference in 762X39 amd 223. Maybe the rifle in that caliber needs to be re engineered to have the service life that the 223 has.
Link Posted: 9/22/2004 2:59:49 AM EDT
Link Posted: 9/22/2004 5:09:15 AM EDT
Thanks Tweak, That answers that question for me.
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