I decided to play around with making a goofy little cartridge called the 32NAA. All it is, is a 380 acp necked down to .312. I used my Beretta Model 84BB because all I needed to do was get a barrel and magazine from a Beretta Model 81 in 32 acp and have it rechambered to 32NAA and it was good to go. The barrel dropped right in. No extractor problems, nothing. It just worked. Except for one problem.
The problem is with jacketed bullets. The case neck is so short and has so little grip that on a blowback gun like my Beretta model 84. The recoil spring power is strong/quick enough to whack the bullet back into the case. It doesn't happen on my my cast and bullets. I have a couple of NOE molds that I coat using Hi-Tek that everything seems to work fine with but it is a concern.
I've experimented with trying to adjust the neck tension and using a taper crimp but that is a no go on jacketed bullets.
I was thinking about running a cannelure around the neck of the case to prevent the bullet from backing into the case. However, I'm not sure that any of the cannelure tools from CH or Corbin will run on a bottleneck case. I'm not aware of anyone else who makes a cannelure tool.
If anyone out there has one of these tools can confirm my suspicions I'd appreciate it.