Describe bullet setback and how to prevent it. Also what calibers are inherently prone to bullet setback.
Bullet setback is the term used to describe a bullet being pushed deeper into the case due to forces exerted on it during the feeding cycle.
The way you prevent it is to make your ammunition PROPERLY. Almost no one does this, today.
There are NO calibers that are "prone" to setback. Setback, if it occurs, is due to forces on the bullet during the feeding cycle. The force is exerted on the bullet by the GUN, and its design features. And it varies.
One gun design may "work harder" at setback than another. Some designs avoid the issue entirely. Others actually compound it.
A single shot never suffers from this problem, nor do revolvers. Semis, and tube magazine guns put the greatest "push" on the bullet.
people today accept setback as a common thing, and tell you not to rechamber ammo too much...and they aren't wrong. Ammo makers don't make the most durable ammo possible, (or don't seem to these days), they make it good enough for "normal" use.
I have personal experience with some ammo that showed me setback was not an inevitable thing. Federal 185gr JHP .45ACP, the owner bought 2 boxes in 1980. Gun was a SigSauer P220. He kept one magazine full, as his "defense ammo) for over 20 years!!! The rounds had been chambered hundreds of times (At least). They had been cycled enough that the nickel cases had brass stripes all over them.
The bullets NEVER MOVED. Not any, ever. I measured them, several times over several years. Those rounds were made PROPERLY!!!
He did, finally shoot them up, in the early 2000s, all fed and functioned flawlessly. Setback does not HAVE to happen.
It does happen, and often, because a lot of ammo is made to be good enough, not the best possible.