They are great for penetrating, they have the hidden insert tech. and they pull out of targets much easierr. The inserts are internal so you get a true fight. I used the easton axis, but pulling them from targets was hard, so I switched to the FMJ arrows and love them. Are they actually heavy though. I use a 340, it will travel better then an aluminum, on a truer line, and the K.E. is great.