Stoner Weapon System replacement?

[welsh]

I really liked the Stoner Weapon system from 3rd edition rule and thought they made sense. I also understand Stoner weapons were frequently used by SEAL teams in Vietnam, but that they tended to be kind of expensive and suffered frequent jams. A talented, experienced and sophisticated unit like SEALs might be able to avoid the malfunction problems, but a Morrow Team generally doesn't have elite troops.

So do you have suggestions for a replacement system for the Stoner weapon systems?

I am also wondering what do you folks think about changing the cartridge from 5.56 mm to .308 for carbines or battle rifles?