I just noticed that the unfired diameter of a 380 Auto case (0.374" at the head, 0.373" at the mouth) is darned close to the diameter for a 375 caliber bullet.

This may be a well-known trick already, but it occurred to me that one might be able to anneal a batch of fired 380 Auto caes and swage or pour lead slugs into them. The increase in "jacket" thickness could even give you controlled expansion. If the projectile is swaged, I'm pretty sure the 1 or 2 thousandths difference could be bumped up.

I don't know what to do about the primer hole, or even if the small cross section of that hole would allow gases to dislodge the lead from the fired case (in rifle bullet applications), but I suppose one could leave the hole plugged with the spent primer or run an appropriately sized screw through the hole, up into the lead slug for additional core locking surface.

Of course, 45 auto cases are about right for making 475 caliber bullets, but 1) a guy who shoots a 475 caliber double probably doesn't need to scrounge cheap bullet materials and 2) 45 auto cases are desirable enough that they usually don't spend as much time on the ground as 380's. Maybe these would be of utility to a 475 Linebaugh/480 Ruger shooter.

Has anyone heard of this being done?

H. C.

I had some mixed fire brass laying around and did some measuring. The steel 9mm cases I had were a little over 0.375". The remington brass cases were right at 0.375" at the head, and a little smaller at the mouth. Seating a 38 caliber lead round nose bullet all the way down, nose first in the 9 mm case expanded it full length to 0.375". The concoction seated just fine in a 375 H&H case, and a Lee Factory crimp die actually crimped the 375 case into the filled 9 mm case.

Other than the case head of the 9mm is still hard, non-annealed brass, I don't see any reason why one could or should not fire something like this. I also recognise that trying to get good accuracy and terminal performance will probably be a giant waste of time. Still, I like to make a hobby out of thinking of ways I could better waste my time.

I wonder what a rimless case head at the tail of a bullet does to its ballistic coefficient. Maybe the bullet will whistle.

H. C.

Heck, a primer-fired 9 mm case (loaded in a 375 case with maybe a pinch of Bullseye) might make a great "gallery" load for discouraging the damn cat from scratching the couch.

H. C.

[ 08-03-2003, 05:38: Message edited by: HenryC470 ]