In NRA prone shooting this match up happens all the time. Go to a 600 or 1,000 yd shot and you are going to see the military teams shooting right along side of the civilians. In my opinion they compare rather well, the best of each group very good indeed. The military guys are very tough with metalic sights, as this is all they get to use for the most part, as they shoot irons in the "any sight" portion of the match.
At one time the military was strapped for long range instructors, and they recruited some distinguished expert class civilians to help teach long range riflery. This happened just a few short years ago. There was very little mentioned about it puplicly. I know because I know someone who was invited to go.
SO IMHO they are quite comparable in their skills. They just get to shoot free ammo...sort of anyway
Best regards, Kirk