9x19mm... Parabellum Improved?

[the naked prophet]

Would it be possible, since the 9x19 is a tapered cartridge, to blow out the case to a straight-walled case like the .40, and give it a tiny bit of shoulder? Kind of like a .357 SIG but smaller.

Reason I ask is that a lot of the 9mm+P gets pretty close to the performance level of the .357 SIG. Maybe you could fit just enough extra powder in the case to give it that little extra bit of oomph? Then you could have a gun that performs like the .357 SIG with the capacity of the 9mm.

I dunno, just a fleeting thought. Maybe there's not enough taper to make any difference at all.

 

[Zak Smith]

You should be able to compute the additional volume, and then compare that to extra seating length in a regular 9x19 case, which should give you an idea of the additional velocity you'd gain. You'd be better off just loading reloads to the max OAL that will feed from the magazine and chamber.

 

[ClarkEMyers]

Doesn't need a shoulder, headspacing on the mouth works.

From the hypothetical the resulting straight case, without a shoulder, is like a shorter, very very very slightly over size .38 Automatic (.38 automatic is a straight case nominally .900" or about 23 mm long and smaller than the tapered 9x19 at the case head, full size toward the mouth). The dimensions are all sufficiently close that years ago Spanish guns chambered for the 9mm Largo and marked 9mm/38 were sold as good for both cartridges - not a wise thing to do. (SAAMI has a list of safe interchanges - mostly in name only as when the competition didn't want to use S&W or Winchester on their barrels) Just the same people today will fire an odd assortment in the same chamber or more wisely in the same pistol with different barrels.

In a double column magazine the various full length 9's (.38 Auto 9X23 .38TJ etc.) give .357 performance and full capacity but do require full 1911 length frames. The performance can be achieved -not necessarily safely or wisely - with long loaded 9X19 cartridge cases. Try .38TJ .38Super Comp, 9X23 or any one of the many alternatives currently used in race guns for equivalent performance and higher capacity.

 

[The Lone Haranguer]

Would the neck length (which would necessarily be very short, IMO) be sufficient to hold the bullet in the crimp?

 

[Jim Watson]

The original 9mm prototype, circa 1902, DWM case 480A, actually had a slight bottleneck. The final version of 1903, DWM 480C, settled on the straight taper still used.

I strongly doubt there is enough difference in case volume to matter, especially with the great selection of powder now available.