Actually, it was the 7mm WSM, not the straight belted magnum.
Your point about muzzle brake is exceedingly important. I have yet to see anything bigger than a 30 cal at a match. Actually, I tell a lie; there was someone who came to shoot a match a few years back with a .338LM, with a brake. We let him shoot because he had driven in from pretty far, but this was the only time.
So, in F-open, the 6.5 and 7 are the prefered calibers because you can get some phenomenal bullets with very high BC values and not kill your shoulder. Remember, all your bullet has to do is make a hole in the paper, you are not looking at putting down a T-Rex at 1000 yards.
There is also the cost of ammo/components. A match is 66 rounds or 51 rounds, depending on the format. Bullet selection is critical.
Last edited by FTR_Shooter; 08/28/09.