OMGeverynameistaken wrote:A .45 caliber rifle round is a bit much for small arms. Recoil would make them rather difficult to aim. If you really must have a large round the .303 is generally considered ideal for 'battle rifles' and machine guns, although the trend these days is mostly towards smaller rounds, such as the 5.56mm and 6.8mm.
I would also note that full auto assault rifles are a dying breed. Full auto fire is generally not desirable in a standard infantryman's weapon. You want burst fire and semi-auto.
Military pistols don't generally use super-high powered rounds because pistols are intended as close-combat weapons, the risk is that with a magnum round the bullet will simply pass right through the target, rather than imparting maximum force and expending all of its energy in somebody's innards.
Shotguns should not be issued to sniper teams. A preferred secondary weapon for snipers would be a marksmans rifle (that is, something halfway between a battle rifle and a sniper rifle, such as the Dragunov.) Shotguns would best be dolled out to specialist assault units and to NCO's who happen to like them. Vehicle crews might appreciate them as well, since you don't have a carbine.
Using a .50 caliber rifle for the 'standard' sniper rifle is also inefficient for much the same reason. You don't need that big of a round to kill somebody unless you're shooting from 2 miles away.
Suggested additions:
A GMPG, and an LMG. Mobile fire support is important.
Some sort of SMG. Useful for vehicle crews and assault units.
A carbine. Same as above, if you don't like SMGs.
Marksmans rifle. Like the US M14 or the Russian Dragunov.
Specialist weapons. See the VSS Vintorez, the various weapons used by US special ops, etc.
Also, look into caseless ammunition. Nobody likes leaving a bunch of brass laying around the field. It's wasteful.