hey all, shot my first 400 and 500 yard target today, and im not gonna lie to ya, they sucked. i shoot a 6br 65gr vmax and my best group at a 100 is .151". it could just be me, im kinda new at this but is there a better choice for 400 to 600 yards. it will be for prairie dogs only and would like to stick with a 6br because i already have brass but i still would consider another cartridge. thanks, SPM