View Full Version : Sig 556 - No gas recoil...?

02-28-2011, 8:55 PM
If anyone could help me with this I'd greatly appreciate it. A friend lent me his Sig 556 swat to install a scope. After installing the scope, I broke it down and cleaned it. Now after cleaning it, I can't get the action to cycle (am I using the terminology correctly?), after firing, the next round won't chamber, I have to manually load it with the charing handle.

I read in the Sig manual that adjusting the Gas Valve Position to position B should force the operating rod to function under abnormal conditions, but it didn't seem to do the trick.

02-28-2011, 9:13 PM
What ammo you using? What type of magazines?
1st thing to check is to see if the gas valve is installed properly. It should only move in two positions, and it is a very small click about 2mm turn clockwise to do so to go to the 'dirty' position.

02-28-2011, 10:04 PM
I bet you have wrongly installed the gas valve, there is a tiny indent on the gas valve which locks it in either normal operation or abnormal operation , the valve is locked by the stop pin, if the stop pin (that little stainless steel button on the right side of the valve) does not lock into the indent on the valve your going to get single action only like a bolt action. Its very easy to forget to line the indent up when putting the valve back.

02-28-2011, 10:17 PM
You guys are right. My mistake, i think, was the valve being installed upside-down. Previously the valve would turn to the 11'o'clock and 1'o'clock positions. After re-installing it, correctly, it turns to the 12'o'clock and 2'o'clock positions.