springfieldarmory.com
Go to the rifles section, click on the M1A link, and it'll have a list of the variants.
Handiness vs. Velocity and Range.
The socom 16 IS handy.
BUT
The whole point of carrying all that .308/7.62x51 ammo (heavier than 5.56) is cuz of its added range and power.
You'd be sacrificing some of that with the shortened barrel.
