Thats really amazing when you look at the round next to say a .223. Its not that much bigger, etc and the performance is outstanding for the amount of powder you use. I am into efficient rounds and that is one of them for sure. All those older cartridges w/ significant body taper- .250, 6.5x55, 30-30. .25-20, .30-40 Krag, etc. benefit greatly from being "Ackleyized" for that reason