AR bolt won't stay open on last round
- Thread starter MJS
- Start date
Read post 14
Remove your buffer spring and measure it.
Swiped this from a post on AR15.com
From: TECHNICAL MANUAL ARMY NO. 9-1005-319-23&P AIR FORCE TO 11W3-5-5-42
RIFLE: 11 3/4 Inches (29 85 cm) minimum to 13 1./2 inches (34 29 cm) maximum
CARBINE: 10 1/16 inches (25.56 cm) minimum to 11 1/4 inches (28.58 cm) maximum.
Swiped this from a post on AR15.com
From: TECHNICAL MANUAL ARMY NO. 9-1005-319-23&P AIR FORCE TO 11W3-5-5-42
RIFLE: 11 3/4 Inches (29 85 cm) minimum to 13 1./2 inches (34 29 cm) maximum
CARBINE: 10 1/16 inches (25.56 cm) minimum to 11 1/4 inches (28.58 cm) maximum.
Read post 17
Haha, touche
Sounds like the spring is too long to be a carbine but too short to be a rifle? Hmmmm.
Go spend $10 on a new carbine spring.
Which one do you have?
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Went out and bought a troy industries battle axe stock that had the buffer,spring and receiver extension,springs and buffer appear to be the same as what I had previously installed.receiver extension was the correct size on this one though so that's one issue that is fixed.
Going to try another range day tomorrow and report back.NEA told me to send it back for them to diagnose,don't really want to go through that hassle though.
Pics as promised
Going to try another range day tomorrow and report back.NEA told me to send it back for them to diagnose,don't really want to go through that hassle though.
Pics as promised
Took it back to the range today.
1st mag:magpul p mag.5 rounds,bolt locked open.
2nd mag:magpul p mag,5 rounds,bolt will not lock open.
3rd,4th,5th mag:10 round CAA lar15's,bolt locked on everyone
6th mag;magpul p mag,no bolt lock open.
So it seems after the buffer swap,metal mags are working fine,but p mags won't.
Anything else you guys can think if to fix this?really don't want to send this off for warrenty.
1st mag:magpul p mag.5 rounds,bolt locked open.
2nd mag:magpul p mag,5 rounds,bolt will not lock open.
3rd,4th,5th mag:10 round CAA lar15's,bolt locked on everyone
6th mag;magpul p mag,no bolt lock open.
So it seems after the buffer swap,metal mags are working fine,but p mags won't.
Anything else you guys can think if to fix this?really don't want to send this off for warrenty.
Does the bolt catch paddle move freely and spring back on it's own when you release it?
When it locks back is it catching the bolt face or the front of the carrier?
Pull your carrier out and with the bolt extended can you stand it on the boltface without the bolt moving back into the carrier? Gas rings may be worn out?
Remove your muzzle device separate the upper and lower, remove BCG and put an empty cartridge into the chamber (to act as a plug) then blow into the muzzle and feel how much air is coming out of the gas tube. Should flow pretty easily. The gas block may be misaligned or the barrel may have had the saddle cut to use a non free float forend with the holder thingy behind the gas block and it's sitting too far back causing a restriction.
When it locks back is it catching the bolt face or the front of the carrier?
Pull your carrier out and with the bolt extended can you stand it on the boltface without the bolt moving back into the carrier? Gas rings may be worn out?
Remove your muzzle device separate the upper and lower, remove BCG and put an empty cartridge into the chamber (to act as a plug) then blow into the muzzle and feel how much air is coming out of the gas tube. Should flow pretty easily. The gas block may be misaligned or the barrel may have had the saddle cut to use a non free float forend with the holder thingy behind the gas block and it's sitting too far back causing a restriction.
I'll have to give all that a shot tommorow or when I get some downtime.
Talked to another guy who has a rifle almost identical to mine just a few minutes ago and I mentioned my issue.said he had the same problem with gen 2 p mags.but after his buffer started to wear in,all the mags would work flawlessly.
Next range day I'm gonna put the full case of ammo I just bought down this things barrel and give it a real workout.hopefully that will break in the new buffer enough.
Talked to another guy who has a rifle almost identical to mine just a few minutes ago and I mentioned my issue.said he had the same problem with gen 2 p mags.but after his buffer started to wear in,all the mags would work flawlessly.
Next range day I'm gonna put the full case of ammo I just bought down this things barrel and give it a real workout.hopefully that will break in the new buffer enough.
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1) run the BCG wet
2)Remove the BCG and extend the bolt by pulling on it.
Stand the BCG on a flat surface sitting on the bolt face.
The BCG should not collapse.
If it does replace the gas rings.
3) is it a full auto BCG?
4) Try a heavier buffer.
5) remove bolt catch spring and clip a couple of coils off of it as a last resort.
2)Remove the BCG and extend the bolt by pulling on it.
Stand the BCG on a flat surface sitting on the bolt face.
The BCG should not collapse.
If it does replace the gas rings.
3) is it a full auto BCG?
4) Try a heavier buffer.
5) remove bolt catch spring and clip a couple of coils off of it as a last resort.
A full auto. BCG has more mass than a semi auto or hybrid.
It slows the cyclic rate.
I had a Norinco AR that wouldn't lock back on last round. I swapped the carrier with a full auto from my Stag and it always locks back now.
Another possibility which is very remote but I have seen it before is a broken barrel index pin.
It is a full auto bolt.going to keep running it as suggested by the guy I met at the range with the same rifle.will report back how it works out.
