I just got a Clabrough 10 bore sidelock with 2 7/8" chambers and have put about 200 reloads though it, all with Cheddite primers. Remington and Cheddite hulls have worked fine but Federals suffer light primer strikes about half the time on the first attempt, firing the second time. The Federal hulls also show burnt powder around the primer, which the other two don't. I thought that perhaps the primer pockets were larger in the Federals but they measure the same as the Cheddites, while the Remingtons are smaller and it takes more force to remove the spent primer. As best as I can measure, rim thickness is the same in all three. Not a big deal, but I'm curious about the difference. The Federals go bang every time in a hammer gun.
