Or you could just save yourself the trouble of forming brass, having custom reamers made, rebarrelling the rifle for 30cal, and working up safe handloads, and just buy a .308, a box of ammo and go hunting.

So you gain 1/2" or so of action length and 3-5 ounces of weight. Big deal. Take it from someone who's humped both the M249 SAW (15lbs empty/22lbs loaded) and an M240G (24lbs unloaded) machineguns for MILES, if you are put off by having to hump 4 more ounces of rifle around, maybe you should consider a less strenuous hobby. Cross-stitch maybe?!

Mike