I have used them both & assume because of the added weight of the aluminum get better penetration. Heart shot 2 years ago on elk & went to fletch. Same setup this year except Aluminum-almost identical hit & distance of shot on a Buffalo (size comparable to Elk) & complete pass thru. I must say-I have more pass thrus with the Aluminum (I like that)but as far as accuracy-I keep my shots usually less than 35 yards & in most cases 20 yards or less. good luck in what ever you shoot.