First, make sure the sizing die is adjusted as follows: with the ram at the top of its stroke, thread the sizing die into the press until it makes contact with shell holder, lower the ram, and thread the sizing die in an additional 1/3 turn and tighten the lock ring. This ensures that the sizing die is bumping the shoulder back as well as reducing the diameter of the case. Visually confirm the shell holder contacts the base of the die when sizing. If it does not, the diameter of the case is squeezed down, making the case (and distance to the shoulder) longer.
If you see daylight at the top of the stroke, readjust the die downward and repeat sizing until it disappears. If your case is still difficult to chamber, simply color the case with a black sharpie, and chamber it, there will be a shiny spot where it’s rubbing. This will indicate where the problem lies. At this point reach out to Lee Precision, send us the colored case and the die back to us with a once fired case and we can modify the die to minimum SAAMI specifications.
Our address is:
Lee Precision Inc,
4275 County Road U
Hartford, WI 53027
