I've used Spitfire heads for 15 years with good success with my bow and then with a Horton crossbow. My concern is that I bought a Mission Dagger, and it shoots much faster than the Horton. I've shot the Spitfire practice heads, they fly fine. Is there gonna be a problem with the expandable head flying open after the release. I've been told that with high velocity Xbows it can a problem.