Tim K
04-08-2014, 09:33
Lapua .260 brass on its third cycle. The barrel was chambered with a tight reamer, so the necks don't grow much in firing. The load is not especially hot, and the charges are loaded to the nearest 0.1g. I use a Redding type S bushing die with the expander ball installed.
I'm noticing significant differences in neck tension from piece to piece. During sizing, some pieces will touch the ball on the upstroke and also on the down. On others, the ball wont touch either up or down. When seating bullets, I'll have a considerable variation in how much force is required to seat the bullet. I'd estimate the ones that require more force need maybe 4X as much as the loosest. I'm guessing the cases that don't touch the ball are also the looser ones in seating, but I didn't confirm that.
Neck thicknesses measure the same when measured with a caliper. They have not been turned.
I can't think of a mechanism to explain this behavior. I can guess at two fixes, annealing and neck turning. I hate them both (along with everything else related to loading) so I don't really want to do them if it's not necessary.
Ideas?
I'm noticing significant differences in neck tension from piece to piece. During sizing, some pieces will touch the ball on the upstroke and also on the down. On others, the ball wont touch either up or down. When seating bullets, I'll have a considerable variation in how much force is required to seat the bullet. I'd estimate the ones that require more force need maybe 4X as much as the loosest. I'm guessing the cases that don't touch the ball are also the looser ones in seating, but I didn't confirm that.
Neck thicknesses measure the same when measured with a caliper. They have not been turned.
I can't think of a mechanism to explain this behavior. I can guess at two fixes, annealing and neck turning. I hate them both (along with everything else related to loading) so I don't really want to do them if it's not necessary.
Ideas?