Will I need a regulating gas block?

[acelungger]

My build will be A3 upper, 18" barrel with mid lenght gas system and a A2 rifle butt stock
will I need to use a regulating gas block? I have my barrel and a gas block that I was going to use with a New LAR A3 upper.
I would be great full for any advice.
Greg

[Drifter]

In my experience, it's usually a good idea to put an adjustable gas block on an 18" midlength. The exception would be if the gas port is ~0.080" (+ or - 0.002"). Most seem to be ~0.090+, which usually results in excess gas.

Get the block adjusted for lightest loads and faster burning powders early on, as some get carbon buildup and lose their adjustability over time.

An adjustable gas block is certainly not absolutely necessary, but it helps to get everything tuned appropriately with some setups.

[LRRPF52]

They're better to have than not if you're playing with loads and bullet weights, especially with an extended dwell-time set-up like that using an 18" with mid-length gas system.

[acelungger]

Drifter and LRRPF52,
Thanks for the advice. I will look around today a see what is out there. I have everything I need to put it togehter but if I am going to use a adj. block then I don't have everything! I am not real excited about putting it together because it's cold!
Thanks again.
Greg

[montana]

I put on a Adam Arms gas piston on my 18" AA barrel because of over gas issues. The Adam Arms gas piston is self regulating and it now works perfectly.

[leopard6.5]

acelungger: Here's a link to an adjustable low-profile gas block I found on midwayusa.com

Hopefully the link works okay since I've never done it before.

I have one just like it that is not adjustable and it works good getting under almost any handguard.

http://www.midwayusa.com/product/775354/pri-low-profile-adjustable-gas-block-ar-15-standard-barrel-750-inside-diameter-steel-matte

Hopefully this helps and good luck with your build.

Lee

[LRRPF52]

The Direct Impingement system is self-regulating as well. The vents in the bolt carrier are proof of it, and how they work with the bolt and gas rings. Whatever type of AR15 you are building, you are now the quality assurance/quality control department. You have to focus heavily on balancing your gas system and recoil system, since you are selecting off-the-shelf components. It is even more important when you use a cartridge with totally different gas impulse and volumes than 5.56, and a dwell time that is significantly shorter or longer than around 8 inches from gas port to muzzle.

[Variable]

While we're talking gas blocks....

Why doesn't someone take this gas block:


And figure out how to make it a three position adjustable without breaking the bank or being too cheesy with the conversion.

Hey-- I can dream, right? LOL!!!

[LRRPF52]

I've always wanted an FN-style gas block for the AR's that I need to play with gas settings, like my AR10. Armalite makes a nice gas block for their SASS, which I think is 3-position, and has break-line seals for the gas tube.