Never shot new brass in competition (couldn't afford it) but I always checked my ammo (45ACP and 38Super) in match barrels the day before a match. That way I knew it would function and I got to inspect all the primers at the same time. Once I shot a local match with nothing but split case ammo rejects and never had a problem.. I have had problems with new brass and some once fired brass (stuff had been fired in a full auto sub. gun) that was bulged so much it couldn't be resized!