I bought a Carlson .655 choke (non ported)for my Nova and it worked fine but after reading mulitple post about the Jelly head choke , I bought it yesterday. Wow! what a differance. I was averaging 12 to 18 hits in the kill zone Using the Hevi #5 3 1/2"but with the Jelly Head my count average went up to 20 to 29. @ 40 yards