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Old Gas System Instructions

12871 Views 13 Replies 9 Participants Last post by  TerraShrewsbury
Guys, I get a lot of requests for manuals with the old gas block instructions. I don't have any printed up... Just a PDF. So, here are the instructions on that... everything else is the same as the current ones.


The rifle is equipped with a Gas Adjustment Valve. The purpose of this device is to optimize the system for certain ammunition and for certain environmental conditions. The Gas Adjustment has four positions which restrict varying amounts of gas from impinging upon the gas piston.

The four positions are marked by a series of small dots which have been machined into the Gas Adjustment Valve. When viewed from above the rifle, the dots indicate the gas setting. Four dots indicates the highest setting, while one dot indicates the lowest gas setting.

To ensure the mildest recoil without sacrificing reliability, use the gas setting which throws the spent cartridge cases approximately 8 to 15 feet from the rifle. To change the gas settings:

1. Unload the rifle according to pages 17-18, and use the Bolt Catch to hold the Cold Carrier in the rearward position.

2. Use a 5/8" wrench to remove the gas adjustment nut and lock washer.

3. With a soft instrument, tap the Gas Adjustment Valve toward the barrel chamber approximately 1/8".

4. Turn the Gas Adjustment Valve to the desired setting, as viewed from the top. Make sure the notch in the Gas Valve lines up with the key in the Gas Block. Then reinstall the lock washer and the Gas Adjustment nut. Don't overtighten the nut. (Note: If you cannot figure out how to operate the Gas Adjust Valve, remove the barrel from the rifle according to pages 19-22 of this manual before trying to adjust the Gas Adjustment Valve for the first time).

Customers Using Sound Suppressors

For customers wishing to use the rifle with a suppressor, try the lowest gas setting. If that setting results in recoil which is still too strong, contact the manufacturer for a Gas Valve which is specifically designed for use with a suppressor.

Here's something more useful in the field...
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Lex - Pin this plz? :)
Ahh, I remember that gas system. The good old days...
Alex, can we get an update on the PDW uppers? My XCR upper already has an 11" bbl. so a 10" bbl. would not be an advantage in my case. I would like to see uppers with 6.8 SPC barrels as short as 8". I currently have a 7.5" AR PDW which is great but the ballistics of the 5.56 out of such a short bbl. is dismal. 6.8 SPC out of an 8" bbl. would be ideal ballistically for a PDW in my humble opinion.

Can you make my dreams come true?
MadDog ???
How do you get the Gas Adjustment Valve back out?
Is there any way I could get that PDF from you? I just bought and XCR used and old boy lost the manual.
Terra is back to work today. I don't think you will have a problem getting a PDF from her. You hear this Terra?
How do you get the gas adjustment valve back out?
Thanks. I will have to use something to place between the pliers and the adjustment valve. I was hoping that there might be a better way to do that. Whatever works. :duh:
I don't have the PDF file anymore. It got sizzled during my computer's last meltdown. :duh: so.. what you see is what you get. :p
My version of the instructions:

Order new gas-block and piston. Replace old gas system. Enjoy.
My version of the instructions:

Order new gas-block and piston. Replace old gas system. Enjoy.
Tried that....been waiting for about 2 months now :duh:
Sorry :-\ They only let me have gas blocks when it doesn't interfere with production.
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