I have a CZ 550 in 1/10 twist and I tried many different powders (Varget, IMR 4350, IMR 4064, RL-15) to try and get 100gr Core-Lokts to stabilize. I could not get them to stabilize for the life of me. I've been relegated to the 87gr VMAX and I don't trust them for use on deer. Therefore, I see this gun as my varmint rifle.