finally found a range that has a 300yrds range with talks about adding a 5-600 yds range in the furture.right now i shoot a lrpv in 223 and a tigershark in 308 but have this model 110 in 300 win mag sitting in the back of the safe collecting dust so i'm thinking of rebarreling it for maybe a f-class gun (heard there is a 7-1k range within driving range from me). so what caliber would work in a long action (no brake) that wouldnt destroy my shoulder when i put 100-150 down the pipe in a sitting ?