fal barrel help

[zeek]

so i shortened the barell on my fal. its 3" from the front of the gas block to the end of the barell and permanatly attached the flash hider.(total barell length is 18" so no sbr needed) the question is it wont cycle with the gas nut turned all the way closed or open. the plug is in the shooting position NOT the grenade setting. i drilled the the gas port from the factory 0.098 to 0.108 and still wont cycle, not that 0.010 adds much to the hole cross section. also i have seen the 16.5 barells that DSA has so it has to work. the only thing i can think of is to drill the gas port bigger to get more volume through it but how much is too much?

zeek

[turbothis]

that is a big jump in a 308.
did you check piston to gas block clearance? maybe it is worn and too loose fitting

[zeek]

it has one of those tapco pistons that measures 0.430 i think that is the correct dia. from what i can find the gas port hole on a amd65 is 0.128 and thats with a weaker round. was thinking step it up by drilling 0.010, test firing, then repeating till it ejects. but stopping at the 0.128 size. remember it has less time for the gas to act on the piston due to the shorter barrel. what do you think?


thanks

[Schultz]

0.125 is the stopping point with the gas port. Heres a couple threads from the FAL Files that might help.

http://www.falfiles.com/forums/showthread.php?s=&threadid=233878&highlight=will+not+cycle

http://www.falfiles.com/forums/showthread.php?s=&threadid=108077

[Global Gunsmithing]

so i shortened the barell on my fal. its 3" from the front of the gas block to the end of the barell and permanatly attached the flash hider.(total barell length is 18" so no sbr needed) the question is it wont cycle with the gas nut turned all the way closed or open. the plug is in the shooting position NOT the grenade setting. i drilled the the gas port from the factory 0.098 to 0.108 and still wont cycle, not that 0.010 adds much to the hole cross section. also i have seen the 16.5 barells that DSA has so it has to work. the only thing i can think of is to drill the gas port bigger to get more volume through it but how much is too much?

zeek

open it up to .115, if it still does not function correctly, then replace the gas tube with a known to be new one

[zeek]

thanks for the info guys, i will drill some more and let you know what happens.


zeek

[chili]

You may not need a new gas tube. Just make sure it is tight and positioned correctly. Oh, don't forget to make sure the little gas tube pin is in place too.

[zeek]

so i endend up drilling the gas port out to 0.120 and everything seems to be working just fine.
thank for the input guys,

zeek