[garryc]

Having loaded many 45 colt rounds I found that the accuracy was often below my standards. Obviously, the chambers in a SAMMI spec gun are way oversized, they are made for 454 bullets and black powder loads. Here's what I did;
First I abandoned the use of carbide dies. They size the case to the same dimension it's full length. Taking a lesson from rifle reloading, I only wanted to size enough to hold the bullet.
Using CERROSAFE CHAMBER CASTING ALLOY as a measurement tool. I progressively lapped out a steel die until the back 2/3's ( actual measurement was the length of a 310 cast GC to the base of the bullet) of the die was the same diameter as the fired case. A simple brass rod, slit in the center to the desired length, wrapped with cotton cloth and a drill was all I needed. I used medium grit valve compound at first, then as I got close I went finer. The last step was to polish the entire die with Flitz.
The result were impressive. groups cut in half.
Yes I have to lube the cases, but with the spray lubes that?s no big deal