GFW Posted October 24, 2020 Report Share Posted October 24, 2020 Have rock River AR10. Having issues with bolt after shooting M118 7.62 rounds. Bolt lock forward after about 30 rounds shot through it, dry fires on live round, have to bump stock to release bolt. round removed but bolt locks forward again and same dry fire. After removing bolt found key and firing pin hard to remove. removed and inspected, no issues found, cleaned and reassembled functions good. No issues with win .308 seems only with the 7.62 NATO rounds does this happen. Is it known not to use this ammo in this carbine? Hearing conflicting information on this heard for AR-10 NATO or 308 is fine but heard not the other way? Which is it? Quote Link to comment Share on other sites More sharing options...
Rsquared Posted October 24, 2020 Report Share Posted October 24, 2020 I take it that this is a new rifle. So, first off, you're gonna have to soak down that bolt carrier. These things like to run really wet when they're in their break-in period. Wet, as in they'll sling oil as you're shooting them. I usually give my carriers a mobil 1 bath overnight for new builds. Pick up by the bolt, and sling the oil off it, dry just the face of the bolt, then drop it into the upper receiver. That might help you out. The other possibility is the chamber could be a little tight. If it runs fine using 308, run another couple hundred rounds through it before trying to go back to the M118. Just a couple ideas to get started. Others will be by to pitch in. Quote Link to comment Share on other sites More sharing options...
Radioactive Posted October 24, 2020 Report Share Posted October 24, 2020 Could be a tight chamber and the slightly longer 7.62 is not actually achieving full lock up. Is it leaving marks on the primer when it dry fires a live round? Run commercial 308 until broke in as r squared suggested then try the military version. 308 specs a slightly higher pressure than 7.62 but only by a little. Both are fine in either rifle chamber. go over to the intro thread and tell us about yourself where your located etc. Oh and you don’t have an AR10. AR10 is Armalight You have the rock river version which is a different pattern. DPms is another pattern as well. Many parts are not interchangeable between them - unlike the ar15 which is a mil spec pattern and ar15 parts are interchangeable between the diff manufacturers. Just to keep it confusing. Quote Link to comment Share on other sites More sharing options...
Armed Eye Doc Posted October 25, 2020 Report Share Posted October 25, 2020 I've never had an issue with my Rock River LAR8 with any ammo including milsurp 762. Like suggested, lube it and shoot what it likes before going back to the other. Quote Link to comment Share on other sites More sharing options...
unforgiven Posted October 26, 2020 Report Share Posted October 26, 2020 Same here. Ejected cases has a heavy scuff marks, didn't matter to me as I didn't reload. Wasn't as bad after 500 rds. Quote Link to comment Share on other sites More sharing options...
LGA Posted January 1, 2021 Report Share Posted January 1, 2021 On 10/24/2020 at 10:21 PM, Armed Eye Doc said: I've never had an issue with my Rock River LAR8 with any ammo including milsurp 762. Like suggested, lube it and shoot what it likes before going back to the other. Armed Eye Doc From LGA regarding ammo: Many firearms are finiky about the brand of ammo they like, not all ammo is created equal as well as ability to cycle . I have found Hornady to be best overall may be a little more money but get what you pay for. Run Hornady from 556 x 45 up to 50 cal. Quote Link to comment Share on other sites More sharing options...
unforgiven Posted January 1, 2021 Report Share Posted January 1, 2021 My Lar8 shot everything loved German milsurp. Quote Link to comment Share on other sites More sharing options...
Armed Eye Doc Posted January 1, 2021 Report Share Posted January 1, 2021 I have also shot everything from 40 year old Portuguese surplus to CoreLokt, to PPU, Federal Gold Medal Match 168 and 175 grain, Hornady, Berger Extreme Long Range, Lake City, etc... The only issue I remember having is with soft point bullets. That is a known issue for many semi-auto rifles. Quote Link to comment Share on other sites More sharing options...
mrmackc Posted January 1, 2021 Report Share Posted January 1, 2021 On 10/24/2020 at 1:47 PM, GFW said: Have rock River AR10. Having issues with bolt after shooting M118 7.62 rounds. Bolt lock forward after about 30 rounds shot through it, dry fires on live round, have to bump stock to release bolt. round removed but bolt locks forward again and same dry fire. After removing bolt found key and firing pin hard to remove. removed and inspected, no issues found, cleaned and reassembled functions good. No issues with win .308 seems only with the 7.62 NATO rounds does this happen. Is it known not to use this ammo in this carbine? Hearing conflicting information on this heard for AR-10 NATO or 308 is fine but heard not the other way? Which is it? I'm a thinkin' you need to listen to these guys, you probably are running the break-in on your rifle a way too DRY. These things sling parts around like an explosion, and will gall up without a lot of lube (Mobil 1) is good, it acts like ball bearings for that Bolt and its fellow companions (Pins, cams and stuff.) just don't get it in the chamber. Quote Link to comment Share on other sites More sharing options...
Belt Fed Posted January 1, 2021 Report Share Posted January 1, 2021 Mobil1 is all i ever use on everything. Quote Link to comment Share on other sites More sharing options...
shrade Posted January 2, 2021 Report Share Posted January 2, 2021 1 hour ago, Belt Fed said: Mobil1 is all i ever use on everything. Like BF said; everything , from my '18 GMC to my Recon, 6.5 Grendel, 223 Wylde, Glocks, S&W's you name it. Quote Link to comment Share on other sites More sharing options...
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