AR-10 Extraction Issue

[Josh Elam]

This is a new build that may fire 18-20 rounds well then stack the case 5 times in a row. So far have only shot PMC 147 gr. Have adjusted the gas. Going to try different ammo. I have a slow motion video I can send. We would love some suggestions. Thanks

 

[The King]

Home build?

I see a JP enhanced bolt in there. Proof barrel. Which I know for a fact works together.

What was your gas adjustment process?

Also, pull out the charging handle and look for a giant ass mark on the inside rear from the gas key. This type of issue is frequently caused by a mismatch of proper buffer and tube for the AR10 platform.

 

[bfoosh006]

I would like to see the SloMo video.

Will it lock back 100% when loading a single mag fed round and firing it ?

 

[mtrmn]

A new built large frame AR needs LOTS of oil inside and out on that BCG. Once it's broke in after a couple hundred rounds, not so much.
Just a possibility

 

[mtrmn]

Does the rim of the fired brass show signs of distortion from the extractor, like trying to extract while the chamber pressure is still too high?

 

[louu]

Do you have the right length buffer in there? Does the bolt catch lock back on the face of the bolt and still move back about 1/8 of an inch when you pull the charging handle?

 

[Josh Elam]

It has JP AR10 silent capture buffer h2, Vltor RE-10/A5SR, A5 Receiver Extension Tube, SLR titanium adjustable gas block.
It does lock back when single fed.
The brass shows witness marks from the extractor but not like it’s trying to extract with chamber pressure.
I can email or text a slow mo video to anyone.

 

[The King]

Him - definitely take your charging handle out and look for damage back near the latch. Flip it over and look on the bottom.

The A5 buffer tube isn't correct with the AR10 JP SCS if I remember right. You will get over travel.

 

[2aBaC̶a̶]

Him - definitely take your charging handle out and look for damage back near the latch. Flip it over and look on the bottom.

The A5 buffer tube isn't correct with the AR10 JP SCS if I remember right. You will get over travel.

Yeah I would start there.

It has JP AR10 silent capture buffer h2, Vltor RE-10/A5SR, A5 Receiver Extension Tube, SLR titanium adjustable gas block.
It does lock back when single fed.
The brass shows witness marks from the extractor but not like it’s trying to extract with chamber pressure.
I can email or text a slow mo video to anyone.

vltor.com

"Receiver is designed to use the VLTOR A5 spring and buffer kit only which is sold separately."

 

[Makinchips208]

Extractor and or ejector problem.
Extractor spring is weak more likely, but also could be ejector spring.

 

[Josh Elam]

This is a friends rifle and I’m relaying info.

 

[cas6969]

Edited it, I just deleted everything I wrote.. that first picture now has me leaning towards under gassed. It doesn't look like it truly picked up that bottom round, but rather push it up through bolt drag to the case body.

(of course if it was a timing issue and the pressure was still up while trying to extract, it would do the same exact thing. lmao Okay I take back everything! )

 

[msgriff]

For AR-10/AR308s, the JP SCS requires a custom spacer when used with an intermediate (A5) length RE.

 

[2aBaC̶a̶]

do you have the JP spring kit for the SCS? you might try other springs.

I built a 6.5 CM using SCS and the LMOS and its finicky to say the least. Ive seen guys ditch the JP stuff and all their problems went away.

 

[cas6969]

Bolt comes back all the way.
Starts moving forward'
Case goes up more than right.
Jams in the front of the port.

My first thought is it's cycling too fast.
Since you said you have adjustable gas, I'd slow it way down first.
If it still does it, I'd think extractor/ejector issue.

 

[bigjake83]

Extractor and or ejector problem.
Extractor spring is weak more likely, but also could be ejector spring.

As jimmy has stated it's either your ejector or extractor I've seen this many times, give JP a call and let them know what's going on and they'll send you some new extractor/ejector springs.