BCG Getting Stuck/Binding

[BREWINZ]

I decided to build a lower I have last night. For some reason, I can't get the BCG back when I pull the charging handle. Gets stuck about an inch back. I don't have another DI bolt to try, but the charging handle moves freely in its absence. I should note that I tried my AR9 upper and the bolt wouldn't go back either. Please tell me I'm stupid and it's not an out of spec lower, because I'm not sure what's going wrong. It's definitely binding, but I can't see where. Takedown and pivot pins go in without resistance.

Anderson Lower
BCM MK2 ELW Upper
Sharps Rifle Company BCG
PWS Receiver Extension

 

[84ta406]

Does the BCG move freely when off the lower? Can you remove the buffer and spring, attach the upper again and see if it's binding still?

 

[cams]

What is that all over the neck of your charging handle? Everything looks like it’s been gouged up with a pair of pliers or screwdrivers. You got scraps inside hanging up somewhere from all that?

 

[DW357]

What is that all over the neck of your charging handle? Everything looks like it’s been gouged up with a pair of pliers or screwdrivers. You got scraps inside hanging up somewhere from all that?

Yeah that charging handle looks rough on the side there.

 

[jjm1986]

Something in that spring or the charging handle is the issue one of those I would bet.

 

[SJan]

So the bolt carrier will come out when the upper and lower are separated?

Bolt carrier and hammer interface?
Receiver extension alignment?
Wrong combination of extension, or buffer, or spring?

 

[snax]

Can u push the buffer all the way in by hand?

 

[BREWINZ]

Does the BCG move freely when off the lower? Can you remove the buffer and spring, attach the upper again and see if it's binding still?

Yes. Moves fine in the upper and still binds with the buffer and spring removed.

What is that all over the neck of your charging handle? Everything looks like it’s been gouged up with a pair of pliers or screwdrivers. You got scraps inside hanging up somewhere from all that?

Yeah that charging handle looks rough on the side there.

What you're seeing is grease. The light played a little trick. The charging handle is brand new. Not a scratch on it.

 

[BREWINZ]

Can u push the buffer all the way in by hand?

Absolutely, yes. No issue. Only when they're put together does a problem present itself.

 

[BREWINZ]

So the bolt carrier will come out when the upper and lower are separated?

Bolt carrier and hammer interface?
Receiver extension alignment?
Wrong combination of extension, or buffer, or spring?

Yes. Bolt moves freely in the upper.

As to the combination of parts, I thought it would be OK, but maybe not?

 

[snax]

Absolutely, yes. No issue. Only when they're put together does a problem present itself.

Buffer pin a c-hair too high?

 

[cams]

I imagine you’ve already double and triple checked your BCG to make sure it’s properly assembled, retaining pins and such not sticking out?

 

[SJan]

Try removing the receiver extension, that will tell you if it was out of alignment if the bolt will cycle then. It's either that or it's an issue with the hammer, it may not be cocking all the way

 

[BREWINZ]

I imagine you’ve already double and triple checked your BCG to make sure it’s properly assembled, retaining pins and such not sticking out?

Yes, sir. First thing I did. My blowback 9mm AR upper wouldn't charge either.

Try removing the receiver extension, that will tell you if it was out of alignment if the bolt will cycle then. It's either that or it's an issue with the hammer, it may not be cocking all the way

That's what I'll do later today. Thanks for the tip! (That's what she said.)

 

[PatMcD]

Rifle buffer in a carbine stock?

 

[BREWINZ]

Rifle buffer in a carbine stock?

I really wish that was it, but alas.... no.

 

[greencobra]

It's either that or it's an issue with the hammer, it may not be cocking all the way

betting on this...

 

[Wrench75]

Back your buffer tube out one rotation. It looks like you are really deep on that retainer pin. You only need to be far enough in to just keep it in. It looks like if you go back one rotation you will still have a grip on it. By the look of the finish on the pin and the chewed up front lip of the tube, that's where your problem is. You could assemble it w/o the retainer pin and spring and see if it moves then. I'm betting the tube is just far enough in that it is acting like a wedge.

 

[BREWINZ]

Back your buffer tube out one rotation. It looks like you are really deep on that retainer pin. You only need to be far enough in to just keep it in. It looks like if you go back one rotation you will still have a grip on it. By the look of the finish on the pin and the chewed up front lip of the tube, that's where your problem is. You could assemble it w/o the retainer pin and spring and see if it moves then. I'm betting the tube is just far enough in that it is acting like a wedge.

Thank you so much. Great advice. I'll give it a try!

 

[citoriguy]

How tightly are the optics/magnifier screwed on to the rail? Maybe back off a bit on that and try to move the bolt again.

 

[BREWINZ]

How tightly are the optics/magnifier screwed on to the rail? Maybe back off a bit on that and try to move the bolt again.

Excellent thought. So good that I tried it! No change. Thank you though.

 

[Sweeney]

It has to be something in the lower from what you've said. Pull the fire control group out and see if it cycles or use a Sharpie to color potential areas of contact, cycle the action as best you can then look for rub marks.

 

[Reptile]

I wonder what would happed if your "mortar" the rifle.

I found this:


"When a cartridge gets stuck in an AR-15, you often cannot pull on the charging handle with two fingers hard enough to dislodge it.

The method you are referring to is to pull on the charging handle as hard as you can, and at the same time, slam the butt on the ground as hard as you can.

The mass & inertia of the bolt carrier group will pop the stuck round out of the chamber.

The method is pretty much specific to the M16/AR-15 platform, as most other semi or full auto military rifles have a steel bolt handle attached to the operating rod that can be beat open with a stick of wood, or kicked open with a combat boot heel.

Those methods will not work on the M-16/AR-15."

@cams - would this help?

 

[cams]

I wonder what would happed if your "mortar" the rifle.

I found this:


"When a cartridge gets stuck in an AR-15, you often cannot pull on the charging handle with two fingers hard enough to dislodge it.

The method you are referring to is to pull on the charging handle as hard as you can, and at the same time, slam the butt on the ground as hard as you can.

The mass & inertia of the bolt carrier group will pop the stuck round out of the chamber.

The method is pretty much specific to the M16/AR-15 platform, as most other semi or full auto military rifles have a steel bolt handle attached to the operating rod that can be beat open with a stick of wood, or kicked open with a combat boot heel.

Those methods will not work on the M-16/AR-15."

@cams - would this help?

It might and might not, can’t say until you try. Not a fan though of jacking a loaded rifle like that unless downrange in an emergency, could cause an ND that you don’t want if just range firing.

OP doesn’t have a stuck round though so why would you? Prolly do more damage inside and multiply your problems.

 

[SJan]

I wonder what would happed if your "mortar" the rifle.

Dont do that.
For a stuck case, sure, but not in this situation. Something is either not assemble correctly, or is way out of spec. Looks like good quality parts are used, so I am guessing an assembly mistake, hopefully an easy to fix one.

 

[BREWINZ]

I know better than to mortar the rifle in this scenario. Thanks though!

 

[BREWINZ]

Dont do that.
For a stuck case, sure, but not in this situation. Something is either not assemble correctly, or is way out of spec. Looks like good quality parts are used, so I am guessing an assembly mistake, hopefully an easy to fix one.

That's what I'm hoping! I'm a moron, so it's very likely.

 

[Deleted member 12999]

Did you try turning it off and then back on again?

 

[SJan]

Did you try turning it off and then back on again?

only works if you wait 30 seconds before turning it back on

 

[BREWINZ]

Did you try turning it off and then back on again?

I checked the TCP/IP settings, restarted it, cleared the cache, and still isn't working.