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View Full Version : AR-15 with .22 LR Conversion bolt, how to close off the gas tube


Noonanda
10-16-2012, 7:59 PM
ordered this about a Week ago to build for my daughters for Christmas, plan is to put the 5.56 Bolt away and put in my ciener .22 Conversion bolt.
http://www.ar15.com/forums/t_7_121/1033910_STAG_M_4_Rifle_Kit_Less_Stripped_Lower__55 9_ship_included_Now_Thru_Election_Day.html

The version Im getting has the railed gas block not the A2 front sight

Well was thinking about it today, biggest disadvantage of an AR is it craps where it eats. And a .22 conversion kit is dirty enough as is without the gas tube channeling the crap back into the reciever. Trying to determine the best way to shut off the gas tube without permanently modding the gas system because once the daughters get a little older they will probably start shooting 5.56 more.

Any suggestions?

tanakasan
10-16-2012, 8:06 PM
I have heard to push the roll pin out, cut the tube short and rotate the tube 180 then reinstall the pin.

Yes, costs you another tube (or a used or damaged one?) but closes the port, keeps the handguard indexed and gives back back a bit of velocity loss to boot.

Robert

Noonanda
10-16-2012, 8:14 PM
I have heard to push the roll pin out, cut the tube short and rotate the tube 180 then reinstall the pin.

Yes, costs you another tube (or a used or damaged one?) but closes the port, keeps the handguard indexed and gives back back a bit of velocity loss to boot.

Robert

I was thinking about this as well, might look into buying another gas tube for surgery LOL. Anyone have a damaged gas tube they dont need?

Anyone else got any suggestions, I was also thinking that dependant on how the Railed gas block is held in place (aka screwed instead of pinned) I might be able to adjust it so it shuts off the hole in the barrel and no longer indexes.

wash
10-16-2012, 8:19 PM
If it is a clamp on gas block, you might be able to remove the gas tube and clamp on the gas block backward to block the gas port.

henmar77
10-16-2012, 8:22 PM
just take it off. cleaning under the handguard every thousand rounds is not a big deal. unless your like me and have to clean every session.

akoba
10-16-2012, 8:29 PM
Will this .22lr conversion bolt work on a piston system? It might be off-topic but it just got me curious. I'm new to AR.

Thnx

CK_32
10-16-2012, 8:31 PM
You do know the 22 kit needs the gas tube to cycle right?

bohoki
10-16-2012, 8:33 PM
You do know the 22 kit needs the gas tube to cycle right?

are you on the drugs?

CK_32
10-16-2012, 8:55 PM
are you on the drugs?

I'm pretty sure my CMMG kit uses the gas tube to cycle and if I'm not mistaken the cenier kit isn't far from the CMMG design...


If I'm wrong please explain how the kit doesn't or if my CMMG kit doesn't use the gas tube either... But I'm prettttyyy sure it does..

Enfield47
10-16-2012, 8:58 PM
What about taking the original bolt with you when you take your daughters shooting and running a few rounds of .223 through after they are done shooting to help clean it out?

tanakasan
10-16-2012, 9:02 PM
You do know the 22 kit needs the gas tube to cycle right?
AFAIK they are blowback designs and function w/o the gas tube...and buffer.

OP, missed the "railed gas block, not A2 FSB" in your post. Loosen it and slide it to close the port!

Robert

Don29palms
10-16-2012, 9:04 PM
I'm pretty sure my CMMG kit uses the gas tube to cycle and if I'm not mistaken the cenier kit isn't far from the CMMG design...


If I'm wrong please explain how the kit doesn't or if my CMMG kit doesn't use the gas tube either... But I'm prettttyyy sure it does..

The 22lr conversion is a blowback design.

CK_32
10-16-2012, 9:16 PM
Tha fack!? I always thought it used the gas tube

wash
10-16-2012, 9:27 PM
Think again.

bohoki
10-16-2012, 9:30 PM
Tha fack!? I always thought it used the gas tube

yea i made a pistol from with 80% lower by chopping an m4 barrel and just using the cmmg kit

the gas tube does serve a useful purpose it keeps the barrel nut from loosening

hermosabeach
10-16-2012, 10:54 PM
The gas tube hole does get clogged with the lube from .LR

I have not noticed any significant fowling from the gas tube

As the system is blow back, the conversion kit needs to be cleaned

I just blow break cleaner down the gas tube on mine

To go ghetto, punch the pins, pull the gas block... Le the hole act as a mini comp

Noonanda
10-17-2012, 6:42 AM
You do know the 22 kit needs the gas tube to cycle right?

No it doesnt, it uses blowback operation. The ciener and CMMG kits use the same principle that any normal .22LR Rifle uses.

Principle of operation
The blowback system is generally defined as an operating system in which energy to operate the firearm's various mechanisms and provide automation is derived from the movement of the spent cartridge case pushed out of the chamber by rapidly expanding powder gases.[3] This rearward thrust, imparted against the bolt, is a direct reaction of the total reaction to the forward thrust applied to the bullet and the expansion of propellant gases.[3] Certain guns will use energy from blowback to perform the entire operating cycle (these are typically designs using relatively "low power" ammunition) while others will use a portion of the blowback to operate only certain parts of the cycle or simply use the blowback energy to enhance the operational energy from another system of automatic operation

Noonanda
10-17-2012, 6:43 AM
yea i made a pistol from with 80% lower by chopping an m4 barrel and just using the cmmg kit

the gas tube does serve a useful purpose it keeps the barrel nut from loosening

if you have to worry about the barrel nut loosening I think you have other problems with your gun LOL

Noonanda
10-17-2012, 6:45 AM
I also saw there are companies that make adjustable gas blocks that you can tighten or loosen a set screw to increase or decease the port size similar to the shuster plug for the Garand. might look into it once I get the kit.

TheExiled
10-17-2012, 8:38 AM
I wish there was a way to go about this on the receiver end when Im plinking around and shooting shotgun shells. Shooting the big boy stuff afterwards clears the tube out, and it smokes a bit and smells funny, however it pukes all of that into the upper

wash
10-17-2012, 12:21 PM
I also saw there are companies that make adjustable gas blocks that you can tighten or loosen a set screw to increase or decease the port size similar to the shuster plug for the Garand. might look into it once I get the kit.
I wouldn't really want something like that to get gunked up with dirty .22lr, you might lose the adjustment when you need it shooting centerfire.

Keep it simple if you are going to get it really dirty.

Noonanda
10-18-2012, 1:57 PM
What about taking the original bolt with you when you take your daughters shooting and running a few rounds of .223 through after they are done shooting to help clean it out?

because if I have the conversion bolt only and since the Caliber is marked Multi, no bullet button required on a Rimfire rifle:D

Thats actually what I already do on my regular AR when I shoot the .22 Conversion bolt, but with this one its gonna be a .22 for a long time

21SF
10-18-2012, 2:03 PM
You wouldn't need a bullet button even with the gas tube in place.

Noonanda
10-20-2012, 5:48 AM
You wouldn't need a bullet button even with the gas tube in place.

Im tracking that, but if I was to put the original 5.56 bolt back into the gun I would, dont even need to worry about it this way