AR15 not lock open properly

[y2k]

Got 20in Norinco AR15 with carbine stock (Lever Arms) and using the mags it came with.
Problem:
About 25% of time on last shot, action is not locked open properly. It catches on the bolt Carrier not the Bolt Face as it should.
I was using reloads 55gr at 3050fps and factory federal at 3250fps does with both ammo so its not under gassed. Otherwise its quite accurate and no other problems.
I did notice at first it ejected cases 4-5 o'clock and later to 2 o'clock position using same ammo.

 

[G37]

Clean it really well (including buffer/spring) sounds like the buffer spring might be on the stiff side and if it has that sticky Norinco-grease covering it I'm sure that's the problem.

 

[84wh1]

Try different mags first....if that doednt work, check the bolt catch.

 

[y2k]

Clean as a whistle inside and out.

 

[Beater]

poor mag springs

 

[SSG69]

Mag...change the mag.

 

[y2k]

Norinco mags seem to have stronger spring than US ones I have. The bolt catch is fine and doesn`t bind. I`m wondering if the bolt assembly is traveling too fast?
Never had this in all these years of shooting AR15`s.

 

[Pop]

The follower might be binding sporadically near the top, too low for the bolt but high enough for the bolt carrier.

 

[G37]

Try some 62gn ammo... note changes in function (if any.)

 

[sky52]

Check gas tube to gas key mating area. May not be sealing properly so its undergassing

 

[y2k]

Made special trip to range with US mags. It works worse with US mags. locks on Carriage instead of Bolt every time with US mag. With all ammo trust me its not under gassed.

 

[Greenhorse six]

I know you posted that it is a carbine stock , but is the buffer spring a carbine spring or rifle ?
What kind of BGC are you using , Rifle , auto or mid weight ?
It's all in the details .

 

[FoxAlpha]

Sounds like it's short stroking, BCG is traveling backwards far enough to function properly but not far enough to lock it back on the bolt face.

 

[skoal]

Made special trip to range with US mags. It works worse with US mags. locks on Carriage instead of Bolt every time with US mag. With all ammo trust me its not under gassed.

Out of curiosity did you check your bolt catch?or your short stroking,if your in stoon I lend you my upper and at least you can eliminate any problems with your lower

 

[y2k]

Its 100% Norinco. I think maybe its over gassed and bolt assembly is traveling too fast. As I stated earlier it does same thing with reloads 55 gr at 3050 fps and factory Federal 55gr at 3250 fps. I`am thinking H2 or even H3 buffer

 

[220]

Check lock up pivot lug, I had one shear off, put a DD lever back in !

 

[sky52]

If its not mag then its over gassing too much

 

[y2k]

If its not mag then its over gassing too much

That's what I'm thinking
Who in Canada would carry a H3 buffer?

 

[kbracey]

Do you have a B.A.D. lever on it?
I had exactly this same problem with my Norc.
Removed the B.A.D. lever and problem fixed completely. Everyone was telling me B.A.D. lever is crap anyway.

 

[FoxAlpha]

That's what I'm thinking
Who in Canada would carry a H3 buffer?

Pretty sure red deer shooting center has them on their site.