My wildcat was the "10-45", a 10mm wildcat on a .45 ACP cartridge I designed and built in 1992. This was before the .400 Cor Bon, but my 10-45 was very similar. It had a longer neck and slighlty less powder capacity with an Ackley Imrpoved type shoulder.
Years before I had read about the .41 Avenger, which was a .45 ACP necked down to take .41 caliber pistol bullets. SSK made conversion kits for the 1911 and the round was written up here and there, but did not achieve much popularity. I was publishing a gun book at the time and thought it would be interesting to do a 10mm-45 ACP, the 10mm craze was just then getting going and many good 10 mm auto pistol bullets were available. I discovered that the idea had already been executed by a custom barrel maker, Centaur and it was called the 10mm Centaur. I met a custom pistolsmith, Dave Sample, who sent me one of his super guns for testing & evaluation in that caliber. He was a big fan of the round and had used it successfully in IPSC competition. He said he got better scores with it than with his old standby .45 ACP. The 10 mm Centaur had a comparativley long neck and a gentle shoulder kind of like the 30-06. Even though it was written up in a couple of articles and was available in match and drop in 1911 barrels sold with Redding dies, it never took off.
Around the same time, a gun writer for Gun World magazine, Eric Kincel, necked down the 45 Win Magnum to 10 mm but with a very sharp shoulder, kind of like an Ackley Improved. He shot it in an AMT auto pistol. I knew Eric personally and he was very enthusiastic about the possibilities of a whole bunch of wildcat auto pistol cartridges in the AMT autoloader based on the .45 Winchester Magnum case, especially in .22 and .25 calibers. Kind of like a .223 or a 250 Savage in an auto pistol. I have to admit that I got pretty carried away by some of those ideas too. The problem is, where do you get the custom .22 and .25 caliber barrels for the AMT pistol? Even apart from that, is there really any point to a .223 or a .250 Savage auto pistol? Well, there may be some point, but some one else will have to find it because I lost interest and I don't think AMT is even in business any more.
In any case, I got the bright idea that the magnum length reamer used for Kincel's 10mm wildcat could be used to chamber a barrel to the shorter .45 ACP length in a Bar Sto Barrel and it would make a neat wildcat 10mm round in the 1911 auto pistol. I contaced Al Sraitiff of the Competitor Pistol company in Mass, who had done the work for Eric Kincel and he agreed that it would work. I provided the Bar Sto Barrel (10 mm barrel with a .45 hood) and he sent it back to me complete with reloading dies as well for no charge because I was going to mention him and give him a page of advertising in my book.
It worked very well, giving better accuracy than any .45 ACP I've ever used and providing me with lots of fun. It has a different kind of sensation than the .45 ACP. Hard to explain, but just different. The slide velocity is greater with the 10mm and the lighter bullets. I think the enhanced accuracy may be related to the fact that you can adjust for precise headspacing, just like a bottlenecked rifle cartridge.
Ballistics are about like the .357 S&W in most loadings. I never got too carried away with trying to make a "magnum" because I did not want to pound my gun to death and the moderate loads were great for general shooting. With a scope, this gun was a lot of fun. This was before the .400 Cor Bon and the pistol always attracted a lot of attention whenever I shot it. The brass was very unusual for the time and people invariably asked "What caliber is that thing?" Then they asked to try it. It seemed as accurate for everyone else as for me and people commented on the way it shot, "Kind of different from the .45."
One more thing: With this cartridge I always got my brass back!
I have a bunch of other wildcatting ideas, but will save them for another time.