m14 short recoil/failure to feed

[Doorgunner]

gentlemen, im having a problem with my m14. first of when i first got this norinco m14s i immediately took it apart and swapped out parts with some usgi i had laying around. my current setup is as follows....usgi unitized gas cylinder with sadlak piston, trw bolt, trw trigger group, nm spring guide and wolf op rod spring w/ buffer, some other things as well but i dont think they will pertain to my current problem. the rifle is completely extracting spent brass and failing to chamber new round from magazine. i have 6 different mags both norinco and usgi and the problem persists. gas port hole lines up from barrel to gas cylinder, there is no junk in the gas port hole, and gun is well lubed where it should be. any help on this issue would be greatly appreciated.

 

[aric84]

Which piston did you get? the grooved or the plain? the grooved will shortstroke on lighter loads, it's meant for the bullets heavier than 170 gr.

Other than that.... i dunno. does the bolt lock back on an empty mag?

 

[Doorgunner]

it is a grooved sadlak piston, that might well be the problem... the bolt does not lock back as well.

-thanks aric

 

[DASQ]

if the bolt does not lock back, is something restricting it from travelling fully to the rear?

And yeah, the NM pistons are meant for heavier loads.

 

[Ripstop]

wolf op rod spring w/ buffer

Try taking the buffer out of it and see if that helps.

 

[Satain]

it is a grooved sadlak piston, that might well be the problem... the bolt does not lock back as well.

-thanks aric

National Match Piston

IMPORTANT: THE NATIONAL MATCH GROOVE IS INTENDED FOR
NM GRADE AMMO ONLY AND IS NOT RECOMMENDED FOR
SURPLUS BALL AMMO OR OTHER LOWER POWER AMMO.​

Check this website out for more info;
sadlak.com/si_rifle_parts_pistons.html

 

[miljew]

make sure you valve spindle is vertical not horizontal. i got a norc to start and after almost going insane with that problem i found out that was the issue

 

[maple_leaf_eh]

Spring resistence. I think the spring isn't compressing enough or its travel is impaired by the buffer. Take out the buffer.

If that doesn't change, try a round rod spring guide to keep the coils aligned or start snipping coils off.

 

[punkrockboy]

I once had this same problem. I gound the buffer down to about half of the original thickness, that fixed the problem.

 

[Doorgunner]

Thanks very much gentlemen.