Rebarrel it to 50 unless you want a conversation piece.I got a MachV that is way overbore & they dont make a bullet resonably priced to take 5000fps.You could build something off the shorter spotter round but your still gona need all the reloading eqip.
I have ben kicking around the idea of shorting a BMG case down to 120grains for a switch barrel 338 as long as I have the stuff to reload the BMGs anyway but to get started in reloading this animal is $$$$. The case in the middle is a 223 with the 375250grai Barns(MachV) on the left=CJ
