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Posted: 7/31/2017 10:39:04 AM EDT
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After trying two barrels and two bolts I finally got a set that would close on a Clymer go gauge and not close on a no go gauge. Barrel is a premium 18" BA and BCG is an Aero nitride version.
Used a geissele reaction rod, torqued/loosened 3 times to 65 foot lbs. had to file down one knob of the barrel nut as it timed directly where the gas tube slides in and was interfering. Using a BA rifle length gas tube. I hand cycled everything at home with lube after cleaning the barrel and BCG. Then went to range and went through 18 rounds of 168 FGMM. Only had one box and not other types on hand. Questions below: 1) after just hand cycling at home I noticed the barrel extension was peened at about 12 and 5 o'clock, same leading right front edge on each of those lugs. Cause for concern? No damage to corresponding spots on the bolt expect some of the nitride coating has come off right at the edge. When I slowly lower the bolt, sometimes the lugs on the bolt hit those two spots on the barrel extension. Other times the lugs are perfectly lined up and slide in. When I assembled the upper the barrel had some left/right play when slid all the way in. I tried to split difference when tightened down. Unsure if I loosen and try to rotate. 2) tested unsuppressed first. First round fired, ejected strong at 3oclock and bolt locked back. Second and third rounds did the same. The fourth round just barely ejected. I had not changed the gas setting on the block and was using the same single load method from a new 10 round pmag. Thoughts on the poor ejection? The extractor and ejector looked fine. When I recorded the next few rounds it looks almost like the case is bouncing around inside the ejection port first. The brass from the first 3 rounds looked good. No primer flow, so issue with base and no dings in the case neck. After these three rounds, all subsequent rounds (I was adjusting gas) had case neck dinged from hitting deflector I presume. 3) I kept adjusting the gas thinking it was not getting enough but even all the way out it still will not lock back. It always reset the trigger and would load a second round when I loaded two but won't lock back. The 10 round mag I used the most now has a gouge in back of follower. When gas block closed off the bolt did not cycle as I knew it wouldn't. Gas block did not seem to rotate and 'should' be lined up correctly with port on barrel. 4) when I added a suppressor the bolt locked back 100% IIRC but ejection was barely clearing the port door. It looked on video like the rounds were coming out, hitting the deflector on upper then back into upper then spit out. The first round suppressed locked the bolt back but case had landed back in port backwards after hitting deflector. Second the bolt locked back and ejector short at 5 o'clock. Third hit deflector and landed about 1.5 feet from rifle at 3oclock. Rifle specs (all parts brand new except gas block) M5E1 set BA 18" premium rifle length barrel BA gas tube SLR adj gas block (worked perfect on last rifle) Aero Nitride BCG Aero 308 LPK Aero 308 carbine spring and buffer kit Magpul STR stock Silencerco brake Larue MBT Magpul 10 and 20 round pmag BCM 308 charging handle Big concern is peening of barrel extension in those two spots. Second is obviously getting it to run correctly. Should I try a heavier buffer spring? Thank you |
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