Monday, December 12, 2022

.327 Short Magnum

In a discussion elsewhere, someone was asking about the possibility of a J-frame sized six shooter using moon-clipped .30 Super Carry.

In addition to the fact that ballistically speaking, .30 Super Carry is just a short, rimless .327 Federal Magnum, there are other issues, some mechanical and some having to do with market realities and consumer buying habits...
All things being equal, heavier bullets are more likely to jump crimp, as they have more inertia.

All things are not equal, though, and lighter bullets...especially with autopistol chamberings that are very sensitive to a consistent COAL...tend to have less bullet seated in the case, so therefore less bullet area for the case crimp to grip.

Combine that with autopistol cartridges being taper crimped* rather than roll crimped, and you get the crimp jumping problem. Premium defensive cartridges that are carefully crimped and have sealant applied to the case mouth tend to be resistant to this, but who wants a revolver that requires you to practice with HST?

Further, if the revolver is set up to headspace .30 Super Carry on the case mouth and the rear of the cylinder was clearanced for rimless rounds in moon clips, then you wouldn't be able to run .327 Fed Mag, .32 H&R Mag, or .32 S&W Long (or .32 ACP in a pinch) which is one of the attractions of .327 Fed revos.

I think a .312" projectile, either a 95-100gr flat meplat SWC at 900-1000fps, or one of the modern 100-115gr JHPs at .30 Super Carry/.327 Fed velocities, is a nearly ideal personal defense handgun cartridge; largely equivalent terminal performance to .38/9mm, while being easier to shoot and holding more BBs in the same size package. It only falls down versus 9mm in some of the more difficult barrier tests like auto glass and sheet metal, but those aren't as important to the private citizen.

All That Being Said™, the ubiquity of 9mm and .38 is a tough hill to overcome in the market. Plus we still haven't convinced everyone that Nine Is Fine, so trying to sell them on esoteric arguments for an even smaller round is like pushing rope. Witness how fast everyone abandoned the P32 for the P3AT, when the former is, with both firearms loaded with FMJ, an absolutely superior alternative. People want the bigger bullets. And the holler points.
*And that taper crimp is sometimes bordering on nonexistent for cheap FMJ range ammo. Hence the Boberg problems...