Hello

I am frustrated with this build used all quality components and having a cycling issue. I had an adjustable seekins gas block which I swap for a standard gas block in hopes it would resolve my issue my rifle will not cycle at all it doesn't eject the brass it fires and that's it. What is going on here.

Parts

Rainer match barrel 308

Standard gas block

Seekins gas tube

Cav arms A1 buffer and stock

Red barn bcg

Any quidance is greatly appreciated

Mike

Not even close to enough information, please describe exactly what is going on and what you've done to fix the problem.

And FYI, almost every AR10 needs an adjustable Gas Block to run smoothly.

Seekins Gas Tube? Exactly which one? I don't think Seekins sells an AR-10 pattern gas tube. If your using a rifle length AR-15 gas tube, that's your problem.

Had to put a SLR Sentry 7 adjustable in mine to get it to run well. Not sure why you swapped an adjustable out for a regular gas block in hopes of fixing it. Can't really help you more based on your info though, pretty vague.

I had opened the gas block all the way and still wouldn't cycle so I taught maybe run a regular gas block still won't cycle. I am running a rifle length tube it very well may be an ar15 tube. The issue I'm having is bolt isn't moving after firing it's almost like a bolt gun .

So what's happening is I fire the rifle but the bolt doesn't move ( cycle ) to eject nor strip another round to chamber it is functioning as it has no gas. I had swapped the adjustable block because I had it opened all the way and it would stove top the brass causing jams. My train of taught was I wasn't running a suppressor so f it and throw in a standard block and run it. AR10/15 gas tube are the same thing. I was looking for some one who had similar issues

DPMS pattern barrels are, Armalite pattern barrels aren't. Are you sure the barrel is a DPMS pattern barrel? Gas block on backwards? Gas tube upside down? Gas port not through to bore? Gas key obstruction?

It's a dpms pattern barrel I am going to take the entire thing apart tonight and check all the above great questions

What is the exact length of your buffer?  If it's an AR15/M16 rifle buffer, it's wrong, and won't allow the cases to eject because of restricted carrier travel.

Can you lock the bolt to the rear?  Does it catch on the bolt catch?

You can't just slap parts together with AR10/LR-308 builds and expect them to work like an AR15.

There are no standards in the market for:

Receivers
BCGs
Gas Tubes
Extension Tubes
Springs
LPKs
Barrels
Barrel nuts
Magazines

You never know if the company you bought the receivers from tested complete rifles with the magazines you intend to use, even if they say SR25/PMAG compatible.  There are all sorts of SR25 look-alike mags, and several generations of PMAGS with significant enough differences to make a gun that worked no longer work.

I think your first problem is the AR15 buffer, if that's what you used.

Lets start with the ammo you're using. What brand, bullet weight and design is it? If you're using hand loads list the specifics, brass, primer, powder type and charge weight and bullet with seating depth.

I own two Armalite AR-10's, a 21" and a 16" and both are reliable when using M852 or M118 ammo. I'm running Slash's heavy buffers in both rifles.

It sounds like you aren't getting any gas at all from the barrel. If that's the case you need to double check the gas block alignment, some gas blocks need a little space between the block and the barrel shoulder to center the gas port in the gas block's opening.

Did you inspect the gas port when you were assembling the rifle to make sure it was drilled all the way through the barrel?

You may be turning the adjustable gas block the wrong way, choking off all of the gas. If you have a compressor use it to check that there isn't any obstructions in the gas tube/gas block assembly.

Finally, it is possible to install the gas tube upside down which makes semi-auto operation impossible.

Make sure you installed the right length gas tube. Currently there are six different gas tube lengths on the market. Your .308 rifle probably needs a mid-length or a rifle length gas tube. Make sure the rifle is unloaded, remove the magazine, lock the magazine to the rear and look inside the mag well inside the upper to make sure the gas tube is sticking inside the upper approximately 1.25"+.

UPDATE?

My $$ is on the gas tube being upside down.

Some people put AR15 gas tubes on an AR10 and don't realize it.

They are very similar in length but one is short enough that a short stroke can occur.


Positive it's an AR10 gas tube?

Did you install the gas tube upside down?

Also, like LRRPF52 said, unless you have an AR10 carbine buffer tube you can't use a regular carbine buffer.


If it's rifle length tube you need an AR10 rifle buffer (which is shorter)

Also make sure the port hole is aligned with the gas block. Some folks just install the gas block up against the shoulder, whereas there should be a space.