A SAAMI 243Win twisted in accords(1-8" if you've the 115 penchant,which I don't,so stated the 105 plainly from inception) will do very nice things from s/a confines,even in OEM guise. Opt an extended internal box(Wyatt or similar) or opt an extended DBM (HS or AICS namely) and things get even better.

In an over the counter modest barrel lengthed rifle chambered SAAMI 243,the .505/105 will do 3100fps,which in a mean-esque atmosphere,will stay supersonic to 1500yds+.