There are lots of different comps you can hang on the end of an M14 shorty. By threading the barrel to 1/2" x 28 tpi, you open up the possibility of using almost any AR 15 comp. Some people rethread the original NORC flash hider to 1/2" x 28 tpi, and mount it. The comp on the bottom is a modified YHM AR 15 comp.
The one in the pic below is the OLDER [ smaller diameter ] version of the Dlask copy of the Miceluk Comp, 1/2" x 28 TPI, originally designed for .223 cal AR 15s. This one has been
Modified for the M14 .... Bored out for .308 cal bullets.
RAUCH makes a ready to mount, slightly modified SS version of the same type comp, designed specifically for the shorty M14, 1/2" x 28 TPI, already bored for .308.
These are big, long, heavy comps, and they work well at reducing muzzle jump to about the same as a 7.62x39 Russian cartridge. BUT, they are LOUD to the sides!!!!.
YHM makes a neat and tidy smaller AR 15 comp with two chambers, that looks like a regular flash hider, and looks great on the M14 shorties, but again you need to re-bore for .308 bullets.
For my personal M14 shorties, I have switched over to the Dlask copy of the PWS TTO comp, again bored out for .308.
YPMMV