AR-10 Issues

[Wendell Reich]

I'm not new to building ARs, I have built a fair number of ar-15's. Just built my first AR-10. A 22 Creedmoor. Have issues.

Aero Precision upper and lower
Magpul magazines
AR-10 JP captured spring buffer system
Superlative Arms adjustable gas block
20" BSF 22 Creedmoor barrel

First, when the BCG tries to go into battery, occasionally, it won't. The extractor doesn't grab the shell. I'll pull back to eject a case and it stays in the chamber. (Case will fall out of the chamber easily. Doesn't seem to be a tight chamber) If I let the BCG slam forward again, it usually picks it up. I made sure it was oiled sufficiently. I think it's getting better.

I get stovepipes. A lot. Ejection is at about 1:30, but weak. Often the brass is on the bench after I shoot, if it isn't sticking out of the ejection port. I started with gas block set to full open. Closed it a bit, which didn't really change anything.

I get inconsistent long gouges on the neck, I'd guess about 25% of my brass shouldn't be loaded again. It's not every case. I didn't pay close attention to it at the bench, but 1/3 of the brass doesn't have the gouges. It's possible that what was causing it, fixed itself.

I removed the BCG and stuck a piece of brass below the extractor and simulated an ejection by letting it go. Plunger spring seems ok. Maybe I'll try it side by side with another bolt to see if it seems weak. I have a Rock River in 308. Rock River BCGs are longer. Wonder if I could use that bolt in this gun?

 

[Zen Archery]

First, when the BCG tries to go into battery, occasionally, it won't.

Boxed ammo or hand loads?
Do you have standard spring & buffer to try?

The extractor doesn't grab the shell. I'll pull back to eject a case and it stays in the chamber. (Case will fall out of the chamber easily. Doesn't seem to be a tight chamber)

What's your gas length and standard or adjustable block?
What BCG? Aero?

If I let the BCG slam forward again, it usually picks it up. I made sure it was oiled sufficiently. I think it's getting better.

I get stovepipes. A lot. Ejection is at about 1:30, but weak. Often the brass is on the bench after I shoot, if it isn't sticking out of the ejection port. I started with gas block set to full open. Closed it a bit, which didn't really change anything.

Sounds like gas issue.

I get inconsistent long gouges on the neck, I'd guess about 25% of my brass shouldn't be loaded again. It's not every case. I didn't pay close attention to it at the bench, but 1/3 of the brass doesn't have the gouges. It's possible that what was causing it, fixed itself.

Polish your feed ramp

I removed the BCG and stuck a piece of brass below the extractor and simulated an ejection by letting it go. Plunger spring seems ok.

How many rounds down pipe?

 

[Wendell Reich]

Boxed ammo or hand loads?
Do you have standard spring & buffer to try?


What's your gas length and standard or adjustable block?
What BCG? Aero?


Sounds like gas issue.


Polish your feed ramp



How many rounds down pipe?

New gun. This was the first time it's been fired.
Hand loads. Different charges. Some hot, some mild.

If the spring and buffer in a Rock River will fit, I can try that. If not, springs and buffers aren't that expensive.

Rifle length. SA adjustable gas block.

BCG - AR-STONER LR-308 Bolt Carrier Group Nickel Boron

 

[Wendell Reich]

Sounds like gas issue.

Yes, sounds like it, but it does this whether I charge it by hand or if it's fired. Maybe that extractor spring is stiff?

 

[BRADMOTO]

I'm not new to building ARs, I have built a fair number of ar-15's. Just built my first AR-10. A 22 Creedmoor. Have issues.

Aero Precision upper and lower
Magpul magazines
AR-10 JP captured spring buffer system
Superlative Arms adjustable gas block
20" BSF 22 Creedmoor barrel

First, when the BCG tries to go into battery, occasionally, it won't. The extractor doesn't grab the shell. I'll pull back to eject a case and it stays in the chamber. (Case will fall out of the chamber easily. Doesn't seem to be a tight chamber) If I let the BCG slam forward again, it usually picks it up. I made sure it was oiled sufficiently. I think it's getting better.

I get stovepipes. A lot. Ejection is at about 1:30, but weak. Often the brass is on the bench after I shoot, if it isn't sticking out of the ejection port. I started with gas block set to full open. Closed it a bit, which didn't really change anything.

I get inconsistent long gouges on the neck, I'd guess about 25% of my brass shouldn't be loaded again. It's not every case. I didn't pay close attention to it at the bench, but 1/3 of the brass doesn't have the gouges. It's possible that what was causing it, fixed itself.

I removed the BCG and stuck a piece of brass below the extractor and simulated an ejection by letting it go. Plunger spring seems ok. Maybe I'll try it side by side with another bolt to see if it seems weak. I have a Rock River in 308. Rock River BCGs are longer. Wonder if I could use that bolt in this gun?

There isn't an across the board standardization of parts with the large frame/cartridge AR platforms. There is AR10 by Armalite, DPMS pattern used, & proprietary.

If you are working with Aero parts, you are in DPMS pattern category. Aero designates this as their M5 line. Are you using an Aero BCG? The idea of using a RRA BCG is on it's face a bad idea. If you install it into the Aero M5 upper, can you even close the upper into the lower without the tail end of the BCG preventing it?

You need to take the bolt out of the (Hopefully the Aero BCG) and check to see if it will slide all the way to contact of the front of BCG to receiver without getting stopped by the gas tube. This would indicate the gas tube protrudes too far into the receiver and is hitting back of carrier key. Then check the bolt headspace with gauges. God forbid the chamber is cut too deep and the extractor can't get a grab on the rim.

Add weight to the JP spring/buffer system. 5.5oz or swap out to a Sringco orange spring and 5.4oz 308 heavy buffer for testing. Do you have a carbine, adjustable stock, or full stock?

If you have the SA gas block on full open, meaning setting 48 or something, and then you are clicking in to setting 20 and nothing its happening, that is indication of a a gas port too small in the barrel. Try a standard restrictive GB. SA restrictive mode is no good. They are only good for bleed off. (Settings 20-48) Why are you running a bleed off GB? Suppressor use?

 

[BRADMOTO]

New gun. This was the first time it's been fired.
Hand loads. Different charges. Some hot, some mild.

If the spring and buffer in a Rock River will fit, I can try that. If not, springs and buffers aren't that expensive.

Rifle length. SA adjustable gas block.

BCG - AR-STONER LR-308 Bolt Carrier Group Nickel Boron

Oh boy. There's a lot of variances & tolerance stacking at play here.

 

[Wendell Reich]

There isn't an across the board standardization of parts with the large frame/cartridge AR platforms. There is AR10 by Armalite, DPMS pattern used, & proprietary.

If you are working with Aero parts, you are in DPMS pattern category. Aero designates this as their M5 line. Are you using an Aero BCG? The idea of using a RRA BCG is on it's face a bad idea. If you install it into the Aero M5 upper, can you even close the upper into the lower without the tail end of the BCG preventing it?

You need to take the bolt out of the (Hopefully the Aero BCG) and check to see if it will slide all the way to contact of the front of BCG to receiver without getting stopped by the gas tube. This would indicate the gas tube protrudes too far into the receiver and is hitting back of carrier key. Then check the bolt headspace with gauges. God forbid the chamber is cut too deep and the extractor can't get a grab on the rim.

Add weight to the JP spring/buffer system. 5.5oz or swap out to a Sringco orange spring and 5.4oz 308 heavy buffer for testing. Do you have a carbine, adjustable stock, or full stock?

If you have the SA gas block on full open, meaning setting 48 or something, and then you are clicking in to setting 20 and nothing its happening, that is indication of a a gas port too small in the barrel. Try a standard restrictive GB. SA restrictive mode is no good. They are only good for bleed off. (Settings 20-48) Why are you running a bleed off GB? Suppressor use?

RR BCG will not fit, too long. Was thinking of using just the bolt from it.

It will go into battery and fire, just, not every time. Extractor is not grabbing the case consistently.

If I add weight to it, I'm not sure that would help with the stovepipe issues.

Gas block is in bleed off mode, not restrictive mode. Bleeding off more would help the stovepipes???

Yes, using suppressor.

 

[Wendell Reich]

Oh boy. There's a lot of variances & tolerance stacking at play here.

It chambers and shoots fine, most of the time, so it's not an issue of parts being different patterns like RR parts in DPMS pattern upper.

I'm wrecking my brass from stovepipes! If I could fix that, I could probably figure out the extractor issue.

 

[BRADMOTO]

It chambers and shoots fine, most of the time, so it's not an issue of parts being different patterns like RR parts in DPMS pattern upper.

I'm wrecking my brass from stovepipes! If I could fix that, I could probably figure out the extractor issue.

Oh ok...

 

[rpol98]

Yes, sounds like it, but it does this whether I charge it by hand or if it's fired. Maybe that extractor spring is stiff?

if there's two O-rings under the extractor, along with an inner and outer spring, you could try removing one of the O-rings, to help allow the extractor to snap over the case rim as it's going into battery. Maybe polish the face of the extractor to help it slide over the case rim.

i agree with the polishing of the sharp edges of your feed ramps to alleviate the gouging of the brass on chambering. Maybe deburr & polish the sharp edges, corners of the barrel extension lugs at 3 o'clock to mitigate against gouging on extraction.

does sound under-gassed. I cringe at the thought of the Midway "house brand" large-frame BCG.

 

[Wendell Reich]

if there's two O-rings under the extractor, along with an inner and outer spring, you could try removing one of the O-rings, to help allow the extractor to snap over the case rim as it's going into battery. Maybe polish the face of the extractor to help it slide over the case rim.

i agree with the polishing of the sharp edges of your feed ramps to alleviate the gouging of the brass on chambering. Maybe deburr & polish the sharp edges, corners of the barrel extension lugs at 3 o'clock to mitigate against gouging on extraction.

does sound under-gassed. I cringe at the thought of the Midway "house brand" large-frame BCG.

Gotcha. I'll check the o rings/springs, do some polishing.

What BCG would you recommend? I think I can return this one.

 

[rpol98]

Gotcha. I'll check the o rings/springs, do some polishing.

What BCG would you recommend? I think I can return this one.

sorry, i'm not familiar with which companies offer BCG's in 22 Creedmoor, I'm not vested in that caliber, ignorance on my part. My large frame AR's are 308 and 6.5CM only, the easy ones.

 

[Wendell Reich]

sorry, i'm not familiar with which companies offer BCG's in 22 Creedmoor, I'm not vested in that caliber, ignorance on my part. My large frame AR's are 308 and 6.5CM only, the easy ones.

Same bolt.

 

[rpol98]

Same bolt.

had to review my notes.

seems my favorite BCG's are Aero nitride, and Brownells nitride. I've also used Rubber City Armory, KAK, and Toolcraft.

I only buy the Aero nitride when it's on significant sale, and try to get the Brownells nitride with promo codes or discounts. I view the Brownells nitride as a lower-cost equivalent to the Aero nitride, having looked at them side-by-side, JMHO. The Aero nitride and Brownells nitride are "HP", smaller diameter firing pin, and associated smaller firing pin hole in the bolt face.