Gunsmithing 8. HOW-TO: Ultimate AR Adjustable Gas Block

[Hellbender]

Part 8:

For those that use the JP Adjustable Gas Blocks (& some other brands), I don't like the single set screw that is supposed to be secured with Locktite (which breaks down under high heat, like a gas block).

So I add an extra set screw that locks the gas adjustment screw...

PS: I also always use a CLAMP on style gas block in a small (.750" or smaller dia.) barrel, as I've heard of the set screw type actually deforming the bore of the barrel when tightened.

 

[mjh30]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

Simple but brillant

 

[AXEMAN]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

nice mod. i am getting a PRI gas block. makes me wonder just how adjustable it is when they advise using loctite on the screw.

 

[Hellbender]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

Axeman...

If you are building a precision AR, I would look at some of the clamp on blocks, instead of the setscrew type.

They WILL deform the bore, no way around it....... if it's enough to matter, I can't say, but I like to remove all the question marks I can.

 

[SIG383]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

what are some of the other adj gas block brands that are clamp on?

 

[Hellbender]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

JP makes several models, and there's another knock off of the JP aluminum railed model, but I can't remember who makes it.

 

[308sako]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

deleted in protest

 

[AK10mm]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

Hellbender,

Ever thought about putting these mods you do in pamphlet form ? Some good info in your posts.

 

[dmg308]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

I drill taper pins on all gas blocks no better way IMO.Your set screw mod is a good step.

 

[Hellbender]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

dmg308...

On a combat gun, I agree, nothing is better than taper pins.

But, this is a match gun only and will probably be apart many times in it's life, new barrel once a year, etc, etc.

And, from an engineering standpoint, for PURE accuracy, the pins WILL deform the bore slightly.....again, no-one MAY ever be able to tell, but a question mark none the less.

 

[dmg308]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

I'll buy that.

 

[dighawaii]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

What an excellent idea you have. I wished my JP Precision gas block came with a set screw. It would have saved me from going to the local hardware store to get a replacement.

 

[pappy42]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

Some high dollar barrel providers dimple barrels for set screw retained type gas bock. I think that they wouldn't do that if they thought the set screw(s) would deform the bore and cause accuracy problems.

I do like the the set screw mod for the gas adjusting screw.

 

[Hellbender]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

Pappy42--

Honestly, on a normal bull barreled gun with the larger dia. (OVER .750") gas block boss, it would probably never deform enough to matter, but why have a question mark on a $600+ Kreiger barrel? The more of these question marks I can remove, the better I like it.

 

[Pat M]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

marked as i'm about to install one

 

[Sean the Nailer]

Re: 8. HOW-TO: Ultimate AR Adjustable Gas Block

Thank you (re-post before deletion)