Ar-15 300-221 Sbr
 

I am in the process of getting an upper together.

I currently have a Krieger bbl that my brother has machined for me. I have yet to set the gas block or drill the gas port or cut muzzle threads.

I know I want to put the gas port in the pistol position (like it ought to be). I am kinda up in the air over how to set up the upper for adjustable gas. I have looked at the JP adj. block, thought of making my VOLTAR GB into an adjustable system .. and then I saw the Fulton Armory adjustable gas tube. On Fulton's site they only list a rifle and carbine tube .. do they make an adjustable pistol tube? If not how hard would it be to make my tube into an adjustable system?

Currently the bbl is 14"? or so. I have plans to install this onto an A3 upper with my LaRue 7.0 railed handguard and am thinking I want to cut the barrel back to maybe 1 or 1.5" sticking out past the handguard. Any concerns I should have with this set-up?

ETA: I currently have an SAS 30 cal muzzle break mount silencer waiting on a F4 that will be used with this upper!

I have a 10.5" M1S SBR AR15 & found that I didn't need an adjustable gas block when I drilled my gas port to .086". I am cycling 220gr subsonics, & all types of supersonics. Just curious, why are you choosing a 14" barrel for your SBR?

I have a couple of the carbine length adjustable gas tubes, had problems with both after about 30 rounds....the pinned on block came loose to the point that the pin came out and the block rolls around on the tube....don't recommend them to anyone....

I use the adjustable PRI, JP, and un-adjustable Vltor in the pistol position....have had good results with all three....

that is the current length .. I am wanting to cut it back to about 8-8.5" (leaving about an 1" or so sticking out past my LaRue 7.0 handguards)

Check with Paladin Machine to see if they have a block you want. I have a three way in the pistol position. Untested still due to lack of free time :-(

It goes High - Low - Closed.

tried paladin armory .. but I can't get into their site .. some google crap saying the site is infected or something like that .. got a direct link that works?

Thanks

PM tp555 on this board. Paladin Machine Services != Paladin Armory so far as I know.

I had a JP on my 16" whisper. I didn't really like it becuase getting it set was always a guess and it wouldn't shut completely off. I put one from tp555 on my 10" and love it.

I have PM'ed tp555 .. anyone have a pic of the block that they can share? Price?

http://secure.adpay.com/Images/Items/2100868.Jpg

Offering 2 and 3 position gas blocks for sale.
Requires cutting one inch off your gas tube.
Two position is open and closed or High and low pressure.Three position is closed,low and high pressure.Stainless or parkerised steel.Sizes are .750, .875 .936, and custom
Cost is $60 shipped.Contact tp555@alltel.net or call Paladin Machine at
803-475-7542

(ad copied from Gun Digest online)

I just ordered one for myself in stainless, I cant wait . :grin:

Since I beat Fudmottin to it, here is a pic he posted previously of the block mounted on his barrel:

http://dl.getdropbox.com/u/360586/300-221/IMG_0557.jpg

So its a screw attach gas block .. I am not seeing how this adjusts 3 ways for gas regulation. forgive me. :smile:

The screw is the adjustment. There is a dimple that is hard to see. But it is currently in the closed position. When the notch is vertical, it is in the low pressure (sub-sonic) position. And when the screw is turned 180 degrees from where it is now, it is in the high pressure (super-sonic) position.

The block is held to the barrel by two hex screws underneath the barrel.

It is a solid arrangement. That particular barrel is one inch diameter towards the breach (left) and 3/4 from block to muzzle where it has 5/8-24 threading and a thread protector. It's a 16" barrel made from a Douglas Premium blank with 1:8 twist.

I forgot to mention that the adjustment screw (really a pin) has detents for the three positions just like the selector lever on an M16. So it is held positively in each of the three positions.