How many times have these heads been sharpened. When I finally bought a digital gram scale I was amazed that I could take off 5 grains or more with every modest file tune-up! Assuming both heads shoot perfectly, you're always better off with the heavier head with hardest steel, in case you should hit bone. Greater weight means greater penetration, and Dr. Ashby has proven the worth of heavy heads for front-of-center balance, which also enhances penetration. You didn't say what you'll be hunting. For little blacktails I doubt it makes much difference, unless you hit a scapula. For big muleys or bear, I'd go with the heavier heads, and for those big European boar and elk, neither one is adequate. All of my older lighter heads have been demoted to turkey arrows, or with the tips filed off for a quarter-inch-wide chisel point, rabbits. Dave