Terry G

What is a this cartridge? I've never heard of it. I have six handguns that fire the 9X18 MM round and have fired every kind of ammunition through them I thought was available. I'm missing something? A 9X18 Super?

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gripper

The Czechs loaded BOTH their 7.62x25 and 9x18 mm service loadings a bit hotter than the warm Soviet standard when they were pressured into adopting the 7.62x24,7.62x39 and the 9x18.
There was a CZ82 SPECIFIC loading with a black coated bullet featuring a sintered iron core. I don't know-have you any photo of the JD loading to post? It might be that or some limited run idea that never took off ie 9mmUltra/Super Police

gripper

https://www.jdfirearms.com/products/...1815034027-843
Buffalo Bore Ammunition 9x18 Makarov +P 34B/20 | J&D FIREARMS

gripper

Is this it?

gripper

I used to have several cases of that. I am down to 500 rounds

boati

It's a wildcat, devised by me and a guy who used to post as "Bill Clo". It's as shortened .38 super case, usable in a locked breech 380, so as to gain as much powder space as possible, to go with the big conical base cavity in the 45 gr Split Nose .36 bore bullet. The goal was 1900 fps, but 1850 proved to be about all you can get and some barrels only deliver 1800 fps. Still, that's enough to cause the pre-segmented bullet to break in half and create two diverging wound channels. But it's not AP and you dont get the Mach II effect of overlapping temporary gas cavities being able to destroy vital organ tissue that is not actually touched by the full-length, unstable, hard, sharp-cornered bullet segments. Still, it's 350+ ft lbs, not bad in a true pocket gun.

Terry G

I see now. You invented it hence the JD. What pistols did you fire it in? I'm curious. How about posting a picture of this load? Both the Makarov and the CZ82 are a bit heavy for pocket gun's, but they could be used that way.

BigEd

Metric designation for .380 is 9x17mm ....hmmmm.

Dorobuta

The 9mm Makarov is 9 x 18

John in AR

I thought this sounded familiar:
He used to call it a '9x18JB' ostensibly for "John" and "Bill", not 'JD' for "John Davis". You'd think an inventor would remember the name of his invention...

That said, there's other problems. Since these have to feed from the same magazine as the host .380 round, extending the case doesn't let you extend the cartridge OAL; just won't fit into the magazine if you do. So if we're stuck with the same outer OAL, (if the concept were valid to begin with) just using a hollowbase bullet would inherently gain you the same interior space without the need for extending of length of the outer case anyway.

Shouldn't be a problem, as these non-existent hollowbased splitnose wonder bullets are allegedly longer than their diameter is wide, so there'd be more than enough length to seat securely without needing a 1mm longer case.

Basically, I don't believe it exists. And if it did exist, the same thing could still be accomplished by using the added internal space of the hollowbase itself. But the kicker is that reaming out the chamber of a .380 barrel another millimeter deeper simply doesn't give some magical leeway to load a .380 to 9mm+P power levels. Laws of physics - they apply whether we find them inconvenient or not.

Terry G

So all this is another Melvin fantasy? What a shock! Come to think of it, why would you go to all this trouble? Be happy with a .380, 9X18 MM, or buy a 9X19 MM pocket gun.

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BigEd

Should be 9x18PD as in Pipe Dream (crack or hash).

BigEd

And also if all this effort is to get higher velocity out of a .380 chamberingwhich again is aka 9x17 unless you have a sloppy chamber you just might end up upping the chamber pressure. Fantasy hollow base bullets and "locked breach" or not.

gripper

Still, seeing as I have and regularly use/carry/shoot four pistols in 9x18, I am genuinely curious as to any experiments with or relating to the 9x18 mm case/cartridge and whether such modification to a suitably strong pistol (CZ82 or resprung Makarov PM?) could be feasible.... maybe something like the old Ackley Improved cartridge developments back from in the 1980s and 1990s where, with a suitably recut chamber one could (it example 30/30 Ackley Improved) fire the original/parent case in the recut chamber as well as the Improved-and ALSO fire form the parent case brass into the Improved confirmation??
Admittedly I run everything from standard ball(various sources)to the Buffalo Bore type loadings so I am always curious

boati

the blow back design of the Makarov is the limiting factor, not the cartridge. The makarov case tapers a lot. it's not feasible to use with 380 barrels and breechfaces. I wouldn't have bothered with shortening 38 super cases if just using makarov rounds would work. Give me a little credit.

gripper

Makarov case is a bit more of a straight walled case than the 9x17 or 9x19. And yes, I know it's a blowback,as is the CZ82.
What I was thinking about was any potential to further enhance performance (more so than the Russian PMM High Impulse efforts,the hotter CZ loadings and the Buffalo Bore stuff)by some chamber cut and (by extension case fireforming) without completely abandoning the design.
To Be Fair,when there's been" 3/4 scale.380's 1911 design efforts" I was also curious about the locked breech efforts,and whether or not such a design was feasible to make a 9x18 barrel.
My question (and wandering brainstorm)on the subject is merely this: How much could the existing case design in a standard PM or CZ82(perhaps,as I said with idea of the Ackley type case/chamber altering)be further enhanced? Not expecting to turn something useful within the" bad breath range to 15 -20 yards as needed" into a pocket rifle doubling as an anti tank weapon :-)
But I am always interested in furtherance of possibilities. Even as a thought exercise or for research purposes