Originally Posted by dfrosch
Hi Bill,
Thanks for being patient with me. I don't have any experience with Ackley Improved cartridges(just a couple Middlesteds). But I can't get past the trigonometry in this discussion.
Every member of the standard 308 family has a shoulder that starts at a .454 diameter and 1.560 length from the case head. Each one has a 20º shoulder that tapers to the neck/shoulder junction at a diameter about .031 larger than the bullet diameter. The smaller the bullet, the longer the shoulder. The Ackley cartridges start at the neck/shoulder junction(really .004 back in the Z axis) and the shoulder tapers out at 40º.
If the shoulder starts in the same place on all of them, then it seems like the crush fit needed to chamber factory ammo would be lost on the larger bore cartridges or the smaller ones would have too much of a crush fit.
Is there something wrong with my logic?
Thanks,
Dana