Which gas block? Please help.

[VforVandetta]

Hey guys, a little newer on this forum, new-ish to ARs, 3 years of firearms experience.

I'm going crazy trying to pick out a gas block.

The story in a nutshell:

I bought my AR from a private seller, it was a DIY build. 18" free float, no name upper, no name lower, no name barrel, un-dimpled, fairly mil spec in general besides the diamondhead forend. I got it for $600.

about 500 rounds into it, I developed some FTF problems.

Intermittently : wouldn't strip a round, rounds would nose up and jam the bolt, and failure to LRBHO.

At first I thought it was weak budget brand tula ammo, So I tried others, and it was fine with Wolf .223 and brass.

Then the malfunctions came back. Friends checked it out, and swapped the upper out with a functioning rifle, which worked like a charm.

Eventually we noticed on my upper, there was fouling coming from around the gas block, i.e. gas escaping.

I removed forend, tightened the block against the undimpled barrel and blu loc tited. 300 rounds no problem. Then malfs returned.

Removed forend, REALLY tightened the block, and red loc tited. 400 rounds no problem. Even held up great for the 1st 3 gun match of the season.

After the match... problems returned. I am beside myself at this point. Friends are sick of hearing about my rifle.

I've heard dimple the barrel/don't dimple....

Get an adjustable gas block/don't get one

Clamp on adjustable?

Geiselle with bomb proof but non adjustable?

If geiselle then carbon steel/stainless/nitrided?

I saw a syrac non-adjustable on GB for $75 the other day....

I had a reputable gunsmith tell me adjustable doesn't make a difference unless its a piston AR, and that clamp on is most reliable.... and that he sells clamp on non-adjustables for $45 block plus tube.

what...the hell.... should I do?

Thanks for any input.

Edited April 14, 2016 by VforVandetta

[GringoBandito]

All of my barrels have dimples for the set screws and I use set screw gas blocks. I usually red lock tight the screws and don't have a problem.

Sent while driving 80 mph, eating a cheeseburger and using my knee to steer.

Edited April 14, 2016 by GringoBandito

[jrswanson1]

Some competitors use an adjustable gas block as they can run a super light BCG and buffer, which aids in faster splits. Personally, I had a smtih put a low profile gas block on my rifle. I don't know how but it's still on there and not leaking after five years.

[thermobollocks]

The most recent time your rifle started having problems, had the set screw loosened? Have you substituted a different (known good) BCG as well?

Red Loctite is the kind that responds to heat (500F), which a 3-gun rifle's gas block can reach. It might be time for some Rocksett.

[VforVandetta]

The most recent time your rifle started having problems, had the set screw loosened? Have you substituted a different (known good) BCG as well?

Red Loctite is the kind that responds to heat (500F), which a 3-gun rifle's gas block can reach. It might be time for some Rocksett.

No, they didn't loosen when I went to take them off, they were still tight as a mother. Had to torch it a bit to get them off.

We tried a SA carrier from another friend, he said it was a $100 BCG.

Does Rocksett just have a higher heat tolerance?

If I do go with dimpling my barrel, is there a good video on how to do that? or just drill a tiny divot and i'm good? I've worked on guns a bunch, just not A lot of AR stuff. Didn't wanna just go for it if not indicated.

[Steve RA]

I like the Carbon Arms, it actually clamps on as opposed to the set screws or other less than satisfactory means of attachment.

http://www.carbonarms.us/Carbon-Arms-Gas-Block.html

[TISCHLJ]

Get the old gas block and tube assy off the rifle.

CLean the bcg well, look for burrs on the m4 feed ramps,bcg assys. Clean and inspect the bbl gp and the gb gp and tube for damages.

Clean the area around the gas port on the barrel.

Measure distance to center of barrel gas port from the gas port shoulder area and on gas block.

Watch a couple of ways to line up the gas block on you tube. Install as applicable.

Install the gb onto the barrel,use Blu lock tite at set screws and or body of gb if needed.

You may want to test fire for proper operation prior to lock tite.

[VforVandetta]

Welp, just wanted to give an update.

My rifle is now running 1000% reliable with all types of ammo even the cheapest.

Here is what I did:

I shelled out for a black rain ordnance adjustable clamp on gas block which I got a good deal on, and a new gas tube. I tested that and found the lowest setting on which it would cycle reliably, which resulted in some very mild and pleasant recoil. All the nose ups, jams, and failure to strips, and failure to ejects were gone.

But I was still getting a lot of misfires with tulammo. Good looking primer hits, but no bang. This continued to drive me nuts. I asked around some more and was directed to buy an "enhanced firing pin" which is designed for 7.62x39 ARs...i guess it is a slightly longer pin which punches those hard russian primers a little bit more on the cheap ammo. It was $15 from "Black Rifle Arms"

I installed it, and now my rifle works 100%.

No malfunctions for 500 rounds now. Not one.

I finally love my AR.

Thanks for the help everyone!

-V

[Hi-Power Jack]

Sent while driving 80 mph, eating a cheeseburger and using my knee to steer.

I thought that looked like you when you passed me ...