Q: According to the Lyman Cast Bullet Handbook, the starting load for the 169gn cast lead bullet in the .30-06 is 18.6gn of 2400 for 1635fps. This load is one I have used. Out of 20 loads, I’ve had the primers start to protrude from their pockets on about half of them. The brass used is new, and the primers were tight to seat and I cut the charge by two grains. Can you tell me why primers are backing out of their pockets, especially since I have loaded some jacketed 150gn bullets to much higher velocities and pressure without this problem surfacing?
A: Your experience with primers backing out is not unusual – pressures are just too low with that light load. The firing pin blow drives the cartridge deep into the chamber before the powder ignites, and the primer then backs out because of the excessive headspace. Try increasing the powder charge one grain at a time with that lead bullet until the primers appear normal. Lyman lists lists 29.5gn of 2400 for 2296fps as being maximum with the 169gn cast lead bullet. And another thing. You would be wise to keep these cases separate for light loads rather than use them again with a full charge.