AR 15 adjustable gas block for 20inch?

[fritzthemoose]

Hi,

I have two basic questions.

Would you go with an adjustable gas block for a 20 inch AR 15 and if yes what would be the real benefit? I know that with shorter ones it makes a difference but does it do it with the 20 inch too?

Which gasblock under the Troy TRX? Nearly all I found so far are too big or not adjustable.

[Jesse Tischauser]

The only reason to use any adjustable gas block is if you have a low mass JP bolt carrier, buffer and spring behind it. If you have that stuff along with the Adjustable gas your 20" will shoot like a .22lr. Don't forget the Titan comp as well.

The JP Enterprises gas block or Precision Reflex Inc (PRI) should fit under the Troy hand guard.

Edited July 27, 2011 by Jesse Tischauser

[want2race]

I run a low pro JP adjustable on my 20". I also use the light carrier and light rifle buffer. I've tuned it to "just" lock open with the ammo I use. The rifle is very very flat.

[prreed10]

I run a low pro JP adjustable on my 20". I also use the light carrier and light rifle buffer. I've tuned it to "just" lock open with the ammo I use. The rifle is very very flat.

Same here, but mine is an 18" midlength gas. The low profile fits nicely under my JP Rifle Length Handguard. The adjustment screw lines up with one of the slots. That may be your only issue with the Troy handguard. You may have to drill a hole in it to get to the adjustment screw if your going to cover it with the handguard.

Very happy with how mine all came together.

[fritzthemoose]

The only reason to use any adjustable gas block is if you have a low mass JP bolt carrier, buffer and spring behind it. If you have that stuff along with the Adjustable gas your 20" will shoot like a .22lr. Don't forget the Titan comp as well.

The JP Enterprises gas block or Precision Reflex Inc (PRI) should fit under the Troy hand guard.

thx for the info. I will check if I get them here in Europe. Will also compare the size to the Impact front adjustable one. Not sure if they sell it in the US but its a German one where you adjust at the front. So never ever any problems with getting to the screw. if its comparable size to the JPE or the PRI I might go with it.

[fritzthemoose]

The only reason to use any adjustable gas block is if you have a low mass JP bolt carrier, buffer and spring behind it. If you have that stuff along with the Adjustable gas your 20" will shoot like a .22lr. Don't forget the Titan comp as well.

The JP Enterprises gas block or Precision Reflex Inc (PRI) should fit under the Troy hand guard.

The comp is another issue. I have a AR 15 made in Germany meaning that I run a metric thread so unless I am going to change the thread on the barrel or the comp a European made one would be the better joice

[Polytech]

The only reason to use any adjustable gas block is if you have a low mass JP bolt carrier, buffer and spring behind it. If you have that stuff along with the Adjustable gas your 20" will shoot like a .22lr. Don't forget the Titan comp as well.

The JP Enterprises gas block or Precision Reflex Inc (PRI) should fit under the Troy hand guard.

PRI low pro adjustable will fit under the TRX, there is no room for any sort of locking nut for the adjustment. I just staked/peened my adjustment screw so it won't move. I was initially going to us a longer screw and small nut to lock in the adjustment, but it was too much to fit under the TRX.