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Posted: 12/19/2013 10:53:30 AM EDT
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Is there a difference in the lug size between 5.56 bolts and say, 6.8? I know the carriers are the same. Just talking locking lugs.
It's on a BM 6.8 SPC that I actually rebuilt for him years ago with the correct type SPC II bbl, and other upgrades. It went into battery fine back then. He had two 6.8s as well as 5.56. I don't think he would have swapped the bolt out, and don't want to embarrass him by asking. But there is obvious misalignment when looking from underneath top receiver. It can be forced, but is a bitch to get unlocked. I know he was using SSA ammo for the most part, and hadn't taken it out but once or twice to sight in. I ran a chamber brush through, lubed the bolt, carrier. As far as I knew, only the bolt face should be different between the two calibers.... HELP 
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What concerned me was, he built the other 6.8 without my help, and I wondered if he switched the bolts out thinking BM was "better". I'm not saying he would have tried to chamber a 556 on it.
As far as I can tell, there are NO markings on the entire "BM" BCG. The lugs start touching the bbl extension and stop, unless you use your fingers to push it in further to the point of locking. This is WO any ammo at all. Then, it's plastic mallet time on the charging handle to get the thing unlocked. The bbl I installed at the time was a SS 1/11 16" SPC II by either Ranier, or White Oak IIRC. Markings are on the bottom of bbl about 2" back from FH. Didn't think a few mags of SSA would even be an issue on the bolt group. As many ARs as I've built, this one has me stumped..... |
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Is it worth it to go with the upgraded extractor made by Noveske, or whoever in chrome for the 6.8? Just ordered some Barretts in discount to offset any issues I may have with my Cprod mags.
Just want to get it running great, work up some loads, and get a nice 1-6X tac scope for it. I used to know how to upload pics on here. Who is the best place to store, share pics with to send to arfcom forums? How's it done? Thanks, much to share that way..... 
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