Quote Originally Posted by soup View Post
Retumbo hasn't been the best performer for me in this gun. Granted I haven't spent much time with the gun yet. 90gn Retumbo with either the 200 ELD-x or 200 Nossler AB I was getting 3"+ groups at 100 yds. That and my velocity was all over the place. With the H1000 the velocities were all within 25fps from slowest to fastest.
It is great you have a chronograph. Check your velocity with the Retumbo loads. If it is low (and I am guessing it is) keep working up the charge.

A lot of slow powders need to hit a certain pressure for complete ignition. If your velocity is erratic with slower than expected velocities you didn't hit the sweet spot yet.