Verify, Verify, Verify!
I have an "00" slide that takes adjustable bushings and a few inserts from Bruce Williams. Checked them prior to loading and they were spot on.
I also have a 1/2 inch bar that came with a number of inserts, (non Bruce Williams). Came with the head for .45LC. Each marked and in separate small marked bag. Had one marked 6.5 Bullseye. Threw charges of 7.0.
Now have a 6.5 ordered from Bruce.