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Going into battery means the bolt closing and locking fully in the forward position.
Are you talking about locking back after last round?
I’m having a hard time understanding what you’re asking, which could just be me.
If you fire one round, does it strip the next round off the mag and into the chamber fully so that you can shoot that one as well?
What type of rifle is this?
Are you talking about locking back after last round?
I’m having a hard time understanding what you’re asking, which could just be me.
If you fire one round, does it strip the next round off the mag and into the chamber fully so that you can shoot that one as well?
What type of rifle is this?
It's a no name lower. With an aero upper. I built it myself. The bolt will strip a round out of the mag but not fully go into battery. I then have to pull the CH again to slam it into battery or use the forward assist to get it Into battery. This happens onevery round until the mag is half empty and then it works as it should. almost like a full mag puts too.much pressure on the bolt that it cant go all the way forward
Does it do it with different brand mags? So if you have the bolt locked back, load a full 10 round mag, hit the bolt release it won’t go into battery?
Edited my post since my reply was after yours. So it does it with the first round with bolt locked back? What brand of mags? And do the mags rock front to back after you lock it in?
To the consternation of hobbyists assembling random parts expecting them to work together as on AR-15s having published technical data packages, large frame ARs aren't mil spec unless produced by KAC (Mk11, M110, M110K1) or HK (M110A1 CSASS and SDMR).
You probably don't have enough bolt velocity to chamber a round with the added spring tension from a magazine that's over half full.
That could be because the bolt isn't recoiling far enough to accelerate sufficiently before picking up a round or the spring rate is too low.
If you separate the receivers and depress the buffer with the bolt carrier tail, does the bolt face end up behind the bolt catch? You could not have full travel due to an AR-15 buffer (5.9" not 5.3") bottoming early or AR-15 spring reaching coil bind (may only be an issue with carbine setups).
With one round loaded, does it lock open and catch the bolt? Under-gassed guns can fail to lock open or catch the carrier. That could be gas block not open enough, gas block alignment, gas port too small, gas tube too short, gas key leak, bolt clearance issues, etc.
How long is the spring, how many coils does it have, and how thick is the wire? You could have an AR-15 spring that's not stiff enough.
This 308 AR forum post has the canonical list of things to check: https://forum.308ar.com/topic/19170-waterboarding/
You might get your gun to run better with more lubrication on the carrier/bolt, although IMHO you're better off fixing the underlying problem.
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As mentioned earlier...
You mentioned an A2 buffer... I assume you mean a .308 length 5.2" ish OAL ?
The common AR15 rifle length buffer ( 5.9"ish ) is longer then a 308 rifle length buffer, and would cause issues.
And the Thunder Tactical lower is a 80% lower ?, Correct ?
Did you use the Thunder Tactical lower parts kit ?
Just some thoughts...
Make sure the chamber on your new barrel is clean. Any sticky packing oils can adversely effect function... and skew your testing.
Clean the BCG as well, and lube generously.
Since we all can see you aren't getting enough ummph to over come your loaded mag rounds force on the BCG...
I would double check the above mentioned buffer parts. Your BCG travel might be the issue if it is being limited. Make sure you lube the recoil spring as well. Not dripping wet but enough to allow break-in.
FWIW, Lancers have about the strongest mag spring I have seen. Try using the Hexmags for testing.
I would adjust the Adj. GB until it locks back on a single mag fed, loaded round.
Then open it slightly more for positive function.
I didn't notice what ammo you have tried ... please share that info as well.
And how many rounds have been fired through the firearm ? Break-in matters more in a Large Frame AR.
Bear with us, answer wise... and no offense intended, but Large Frame AR's are hard to diagnose with out hands on. Add in the 80% lower factor... and they can be a complicated matter.
You mentioned an A2 buffer... I assume you mean a .308 length 5.2" ish OAL ?
The common AR15 rifle length buffer ( 5.9"ish ) is longer then a 308 rifle length buffer, and would cause issues.
And the Thunder Tactical lower is a 80% lower ?, Correct ?
Did you use the Thunder Tactical lower parts kit ?
Just some thoughts...
Make sure the chamber on your new barrel is clean. Any sticky packing oils can adversely effect function... and skew your testing.
Clean the BCG as well, and lube generously.
Since we all can see you aren't getting enough ummph to over come your loaded mag rounds force on the BCG...
I would double check the above mentioned buffer parts. Your BCG travel might be the issue if it is being limited. Make sure you lube the recoil spring as well. Not dripping wet but enough to allow break-in.
FWIW, Lancers have about the strongest mag spring I have seen. Try using the Hexmags for testing.
I would adjust the Adj. GB until it locks back on a single mag fed, loaded round.
Then open it slightly more for positive function.
I didn't notice what ammo you have tried ... please share that info as well.
And how many rounds have been fired through the firearm ? Break-in matters more in a Large Frame AR.
Bear with us, answer wise... and no offense intended, but Large Frame AR's are hard to diagnose with out hands on. Add in the 80% lower factor... and they can be a complicated matter.
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Sounds like you need to lubricate the BCG for starters and make sure that’s a correct AR-10 rifle buffer, not an AR-15.
AR-10s especially love to be lubricated.
Magazine cartridge stack tension should not be enough to choke the Bolt Carrier in the raceway.
The Aero upper and Aero BCG should work together correctly.
A problem with “AR-10s” is that very few manufacturers are working off the same critical datum set, so parts that fit together don’t work well together from a mechanical engineering perspective.
One of the first places you see this is the impact of the carrier rails into the lower receiver RET boss area.
The magazine catch height on your (I’ve never heard of that company) lower might not be correct for the Aero upper.
If the seated magazine height is too high relative to the carrier, it could cause the problem you’re having.
I would lube the BCG rails generously and see though.
It would really be best to use a matching Aero lower I think.
Only other issue beyond this excellent advice is magazine sitting too high in the receiver. Only takes 1/32" or less to screw things up.
Factory ammo or handholds? If none of the above works, have you checked headspace? Could be that the chamber is ever so tight and the extra oomph from less spring tension is just enough to jam the shell into battery. Not likely, but possible. Also unlikely but could be that the bullet is touching the lands and is being jammed by the extra force. That is easy enough to check by ejecting and looking at the bullet.
A buddy had to go to a small base die on his factory built ar 10t. Chamber was tight and was squeezing his reloads just a touch. He was having to re rack and jam them in here and there. Small base die fixed it right up.
A buddy had to go to a small base die on his factory built ar 10t. Chamber was tight and was squeezing his reloads just a touch. He was having to re rack and jam them in here and there. Small base die fixed it right up.
