LR308 build cycle issues (FTEject)

[cg&p]

OK all i need some help. I took this rifle to a local gunsmith and while he did help some, he did not completely resolve all the issues my LR308/AR308 build was having (the chamber was either very tight or not finished all the way which he did fix). i have been working on it and replacing parts to solve various issues (firing pin hole in bolt too big, cheap buffer spring, etc.) and i believe i have just this one last issue to resolve. as you can see from the pic the round fires, but when ejected will spin 180 deg in the action and cause a jam.

the rifle has an adjustable gas block which i believe is what the issue is and needs to be adjusted but i am not sure if it needs more or less gas.

i am using a Brownells LR308 BCG as well as a brownells LR308 carbine buffer spring (yes i made sure it was for a LR308 and not an AR15)

if anyone has had this issue themselves and fixed it i would be forever indebted to you...

[wurger]

You can try 308ar.com. After they get done giving you a bunch of crap for using an adjustable gas block, you may get some good advice.

[gpark09]

the rifle has an adjustable gas block which i believe is what the issue is and needs to be adjusted but i am not sure if it needs more or less gas.

Usually need more gas. First, make sure ejector and extractor are working fine. Then, make sure there's no leak in any part of BCG.

Your gunsmith probably has smooth out the chamber at the first time, so rough chamber can be eliminated at this point. The gas block hole was checked, right?

[NATEWA]

When I put together an ar308 upper, I watched this video.

Make sure your gas block is correctly installed. Sounds like you have the correct parts.

https://www.youtube.com/watch?v=Lr6BZl_uyNk

[ar15barrels]

Most common problem is too much gas.
The best way to adjust the gas block is to close it all the way down to start.
Load 1 round in the magazine.
Fire the round and observe what happens.

If the gas is closed down too much, the action will not eject the case.
Now repeat the load-one-and-fire sequence while continuing to open the gas adjustment about 1/8 turn or 1/6 turn per shot.
As you open it up, it will eventually eject, but not lock back on the empty chamber.
Keep opening up until it WILL lock the bolt back on an empty chamber.
That's your ideal setting.

Read more here: www.ar15barrels.com/prod/operation.shtml

[cg&p]

thanks all for the help everyone! i will make sure i have the correct allen wrenches in my bag next trip to the range and adjust the GB.

BTW @ar15barrels it's funny you posted the procedure to dial in the GB. The gunsmith told me to NEVER shut the gas off completely and follow the procedure you describe (even though what you describe is what i was taught) as it would blow apart my lower LOL.

for what it's worth i believe your way to be best as the gun hits max pressure right after ignition and has nothing to do with how much gas is allowed back in by the gas block. so if the pressure generated by the round being fired would rip apart my gun the gas block would not be part of the reason is my understanding.

[ar15barrels]

The gunsmith told me to NEVER shut the gas off completely and follow the procedure you describe (even though what you describe is what i was taught) as it would blow apart my lower LOL.

You might not want to listen to that gunsmith concerning AR's anymore.
The lower is not a gas system component.
All it does is hold the buffer tube, buffer and spring.