In 1989 and 1992 our company was awarded two military contracts for SNIPER RIFLES - in 300 Winchester...
The first contract was for 50 rifles and the second contract was for 100 rifles. When the "actions" were brought to me, they were all Remington 700 long actions with magnum bolt faces. The side of the receiver opposite the port side that usually has "REMINGTON 700" stamped on it, instead had this on it - USMC SNIPER - XXXXX. With pairs of actions having identical serial numbers. When I asked why there was two actions with identical serial numbers, this was the explaination I was given: (Each sniper is given a "pair" of rifles that are 100% identical to each other in every way. One rifle is for field training purposes, maneuvers and training excersises. These rifles are shot and shot alot! The second rifle, identical to the first, is for actual missions in the fields)...
Once I received these actions, they were completely blue-printed. The barrels that were used were Match grade stainless steel, 27" in length and #6 in contour and chambered for the 300 Winchester. All stocks used were McMillan McHale SNIPER stocks. A tapered base for long-range shooting was secured to the action with 6 #8-40 screws instead of the usual 4 #6-48 screws that pretty much everything else uses. 5-steel rings were used to anchor the scope to the base after each and every ring was line bored and lapped. The trigger that was used on these actions were all adjusted to EXACTLY 30 ounces. The first contract for 50 rifles had my muzzle brakes installed on the barrels but the second contract did not...
so basically without getting into too much more, YES - the 300 Winchester was and is used as a military SNIPER weapon but, so is the 308 Winchester and 50 BMG....