AR-10 n 6.5CM Double Feed Fixed

[TxVet33]

So, I built an AR-10-6.5CM from milling the 80% receiver to everything else a year ago. I could never get the gas system to work correctly (I thought). The weapon would double feed from the start. So, it's been setting in my safe for at least 6 months. I went to the range to check my zero on my two AR10-7.62x51 rifles, also built from scratch. These weapons are 3-4 years old now and have always run like a clock, never a hiccup from the get go. This time my 20" 308 started double feeding. I tore down the weapon and found the extractor spring was broken. I ordered extra power spring sets (from LaRue, a great TEXAS company) for all three weapons. Now my 6.5CM is running for the first time. It has an EABCO 22" HB that has only 12 rounds thru it. Can't wait to shoot it now. Been raining here in Abilene, gotta wait for the mud to dry up some. The bolt stick is an Axis in 6.5CM with a 20MOA EGW mount on it. Don't forget to wash your hands too! That stuff don't wash off. "). 11B

 

[clcustom1911]

Good job on finding your issue. Feeding/extracting issues suck, big time. One thing I've found is memorizing the 8 steps of the cycle of operations: feeding, chambering, locking, firing, unlocking, extracting, ejecting, and cocking, (repeat)... and then further learning what exactly is going on with the articulating parts of the rifle during each step and when transitioning from step to step.

I had an AR I put together that used to leave cases of factory ammo stuck in the chamber, and the case rim ripped off. Technically, all the moving parts were working correctly, but my bolt carrier was a lightweight type, and unlocking a hair too soon while the pressure was still high in the chamber and the casing was still pressed out against the walls of the chamber. Gas was pushing the bolt carrier group back and the extractor was pulling on the casing which was under high pressure.

Cure? I initially, and incorrectly reasoned I should polish the inside of the chamber because the rifle had less than 1000 rounds through it. That lessened the problem, but she still flubbed every once in a couple hundred rounds. Unacceptable. So, I had a light bulb moment thinking about the timing and gas pressure issue.... I put in a standard weight bolt carrier, and now she's a kitten to shoot: less recoil because slower bolt velocity and now all my casings eject at 3-4 o'clock instead of 1 o'clock. I even got a velocity boost of 30-40 fps because instead of sending too much has back towards me, it's going out the front behind the bullet where it should be!

 

[TxVet33]

Yes sir correct all the way around. Sometimes just putting it up for a while helps to clear things up so you can think about it. I had about seven other projects going when this weapon was built and I tried to prove its operation. Stepping away helped but I was really frustrated. Thanks for your lesson learned. I’ll copy and paste it. I try to keep little nuggets like that. Keep’ m zeroed. I fear for the republic. Interesting times we live in. 11B

 

[shax2lex]

I think an adjustable gas block really helps on 6.5CM ARs as well.

 

[TxVet33]

Yes sir one is installed along with a silent capture buffer system from arm spec.

 

[shax2lex]

I don’t think I’ve heard of a silent capture spring from Arm Spec. Not to sure about that guy.
I’d say check the gas block to see if the setting came loose. I had the same problem and I had to reset the gas block.

 

[TxVet33]

Nothing is loose. Everything is working. I've zeroed to MPBR with my bullet of choice. Thx men for all the input. Have a great day. I'm off to the range to check my zeros on my 7.62x39 carbines. MAGA. 11B