are muzzle breaks allowed on the 600 yard events on the heavy gun? I noticed the rules say no, but was told that it was changed such that a light gun with a brake could shoot heavy. A light is still 17 lbs or less, correct? Thanks for tolerating a few basic questions. I am trying to decide on shooting the 600 yard event at the VHA jamboree. Is the course of fire 3 5shot groups for each class?