The 2-3/8" BPE version.
Please educate me: Where do you find brass, dies, etc., what bullets are suitable. Lead/jacketed? What's the proper bore size? I'm contemplated building one on a Martini action, but need to know a lot more than I do right now before deciding...

Ped,
I've never heard of, got any pics?

anything 40 cal on a single shot sounds interesting

jeffe

The 450-400-2 3/8 BP will shoot 32 grs. of cordite for black wiht a 270 gr. bullet at about 1600 FPS with a .410 bullet but you must first slug the bore and be sure of the bore size..

80 grs. of black powder is recommended for 230 adn 255 gr. bullets,

Case length is 2.375
Rim thickness is 0.042
Bullet diameter is .410 (slug the bore)

This tells me that you could probably make cases from the 450-400-3 1/4 by trimming them to 2.375 and resizing, I think...but not the 450-400-3" I might add...

Most 41 cal pistol bullets should work and lots of cast bullets available for .410 and .411...Might have to be sized down perhaps as most are .411. Then one might consider trying the .408 or .411 bullets from Woodliegh as they might work very well...

Thats the way I see on the surface, but you may want to research it out further to check out my theories, as I have not owned or loaded for such a caliber...I would also have the gun checked out by a good double smith first of all and seek his advise.

Jeffe:
No pics, but it's listed in the 8th Edition of COTW.
Ray:
Thanks for the info, that's more than I had. But, it's not a double-it's a single shot that I plan to build.
The idea is a classic British round, in a classic British action... The 3-1/4" version might be more practical, but I'm not sure it would "make the turn" in the Martini action. I suppose I could make a dummy stub barrel and try it out...

What would be very practical and classic would be the 450/400 3 inch. A Nitro Express round that has brass and bullets readily available. Most 450/400s shoot .408, 400 grain bullet between 1950 and 2150 FPS depending upon 55 or 60 cordite loading.

It is a wonderful all around chambering that is small enough to shoot a lot and big enough to swat whatever you'd like to shoot.

The 450/400 3 inch will do what the 450/400 3 1/4 (originally a black powder round) will do, at a bit less pressure. The 3 inch is a heck of a lot easier to reload than the 3 1/4.

Just my opine.

Rusty

Pedestal,
Maybe you're not aware of this, but 450/500 2 3/8" is still a factory cartridge, with brass, bullets and ammo still being produced. However, the name is different. Try looking for 10.3 x 60R Swiss - same round, only a modern version This one gets a 330 gr bullet up to 2000 fps, according to COTW. For components, try some swiss shops - this is a classic Swiss hunting cartridge. and yes, this would make a dandy Martini rifle, I also considered your idea. For the moment, I'm staying with 577-450 and 500/450 #2 Musket though... Martini's forever!

Sorry - it is indeed a typo, 450/400 is correct. Barrel dia. is a bit different, but I am sure the brass could be used