*UPDATE* Disappointing outcome - first time out with .308 build

[RUTGERS95]

I know issue has been resolved, but are you using a carbine length tube and buffer? On the .308 you need an A5 length tube to run a carbine length buffer.

If your running a .308 short buffer disregard.

no you don't

standard carbine buffer tube, 308 carbine spring and heavy carbine buffer work perfectly. You absolutely do NOT need a A5. I've gone through 5 builds with this exact set up and not a single hiccup. Use the same manufacturer for receivers and bcg I think is the key. For the heavy carbine buffer (308), I've been using the kak brand and works like a charm for thousands of rounds. You don't even have to get an adj gas block although I did on some.

[czgunner]

no you don't

standard carbine buffer tube, 308 carbine spring and heavy carbine buffer work perfectly. You absolutely do NOT need a A5. I've gone through 5 builds with this exact set up and not a single hiccup. Use the same manufacturer for receivers and bcg I think is the key. For the heavy carbine buffer (308), I've been using the kak brand and works like a charm for thousands of rounds. You don't even have to get an adj gas block although I did on some.

Exactly. I think this is why so many people get it wrong. If I'm not mistaken, you can set up a 308 AR with one of 3 different receiver extensions. Then people mix and match parts from the 3 setups and run into problems.

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[grizzman]

As long as a short .308 DPMS-pattern buffer is used, a standard AR15 receiver extension works fine.

One problem is that often people aren't specific enough when they tell what components they are using. Is it a heavy carbine buffer for the AR-15 platform, or a heavy carbine buffer for the 308 AR platform. These are distinctly different and in no way interchangeable.

Right now, all of mine have A5 length AR15 receiver extensions, AR15 buffers, and Sprinco red springs. I've run a standard AR15 receiver extension with short 308 AR buffer in the past, with no reduction in reliability.

[Backfire]

For my own sanity, my next build.may be a 308.
Should I expect to do a dance getting g it to run right?
This guy had good parts and a Wilson combat barrel that needed attention.
IS 308 a bit more finicky?

[Pappabear]

308 is not a finicky round, but building an AR10
can be finicky. So I’m told. I always just buy full guns even though many have built great guns and spent less.

[dpete]

For my own sanity, my next build.may be a 308.
Should I expect to do a dance getting g it to run right?
This guy had good parts and a Wilson combat barrel that needed attention.
IS 308 a bit more finicky?

Simple answer is yes...308 ARs can be finicky. Mostly because there is no industry standard for making parts like the milspec in the AR15.
To answer your questions go to the same place the OP went to get his rifle running. https://forum.308ar.com/
Quoting from post #39, "The gurus over at the 308 AR forum were a tremendous help."

If you are thinking of building a 308 AR go there. Introduce yourself, read topics that interest you, ask questions, listen to the advice given to you and your rifle will run.

First and foremost....You cannot build an AR10! You can build a 308 AR using any number of manufacturer's parts but only Armalite makes an AR10. AR10 is tossed around as a generic term for 308 AR and it creates nothing but confusion for new builders. Your AR10 is a 308 AR, but your 308 AR will never be an AR10 unless you bought it from Armalite. There is no milspec in the 308 world. A manufacturer can make any part any way or shape they want, and they often do, and to compound the problems and confusion then call them AR10 parts.

[richiecotite]

Having the same issue with a Wilson Combat barrel in 6.5 Creedmoor, 16”, intermediate gas, .750 journal. Was less than .068.

*5/24 edit* drilled out the GP to about .82, realigned the block, and I haven’t had issues in the last 150 rounds since putting it all back together

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[Hammer_Man]

Are these Wilson Combat barrels under gassed because they are designed to run a suppressor? Not trying to be facetious, I’m genuinely curious.

[dpete]

Not saying WC does this at all, but some companies will undergas a 308 AR so they can use AR15 recoil parts and have a firearm that functions (until it doesn't with ammo other than what they use to test function). A lighter weight spring and buffer can save quite a bit of cash over the course of a years worth of rifles. It costs them nothing extra to drill a too small gas port hole and it saves them a lot by doing it.

[TomMcC]

Since your rifle is new, this might help. I had an AR that would short stroke, everything was new. I hand cycled it a bunch, like a 100 times a day for 5 days, before my next range outing. It has worked find since. I believe it was just tight unbroke in gas rings.