Plentiful supply of 30-06 brass, less powder. The largest load by wieght in grains of powder usuage was 62 grains for a given load. Whereas the 338 mag usually starts around 60+ grains and goes up I to the 70's. This round is very effiecent. Also you can fire form 338-06 A-Square in the Ackley version. This rifle also has less felt recoil than any of the 338 win mags I have owned, even though I am duplicating the Win Mags velocities. I built it because I like odd ball stuff lol.