I'm shooting a kmm barrel wolf guide rod and tried both 17 and 22 lb wolf recoil spring. Works pretty well with various jacketed ammo but when I shoot the mihec wfn through it with anything from 8.0-8.5 grains longshot powder it jams. I'm seating them to 1.250". They cycle by hand smoothly and flawlessly. Here is a picture of the kind of jam. Thanks