A shot at over 400m with WWII rifles is a pretty difficult feat. I've gotten to fire a mauser 98k , at a nice 8X6 in coleman fuel can (empty) at the 250 mark, and it took 2 open sighted shots to hit the thing, and the second shot was an outside glance, not in the center. (later, wehn I got to use an M-14 {civilian} my shooting was remarkably better ) The fuel can is probably about the size of a bent over soldier at 500m, and seeing as how hitting it posed problems for a half-way decent marksman on a range, I'd imagine a sniper trying to accomodate hsi cover to his shot, wincing from stray bullets, aiming at a moving target in real world terrain, would have a hell of a shot if he manged to hit.