I have acquired a Martini Henry or to be correct a Martini Enfield where the barrel is damaged so it can not be repaired.
I have been toying with the idea of having it chambered in 450 Nitro Express.
Have anyone done this?
Is the action strong enough for this cartridge?
I am going to have the action checked before doing this.
DPI and harness testing.
Think it will make a neat little package.
Recoil might me an issue, but I think it will be OK.
Any comments

There are so many different models and variations. I recently saw a 450/400 on a mil surp Martini action.

Here is a forum dedicated to the Martini Henry.

Ask them.

http://www.gunboards.com/forums/forum.asp?FORUM_ID=14

If that rifle was originally a .303 you might consider .405 Winchester, extractor would not have to be altered. For your own idea, a .450 Nitro Express is not outlandish, the Brits made many Martinis for large calibres, but most of them were black powder. I am not sure just how good the extraction is, of a long cartridge case, in a Martini. In a nitro cartridge you might have trouble on a hot day. The guys on the Martini forum might have some advice.

The problem might be getting the .450 into the chamber, it has to go 'round the bend' as it were, and at 3 3/4 inches or more OAL might be too long. I know they were routinely chambered for the .375 Flanged Magnum, and a number of other bottle-neck cases, but a long straight case might give problems.

Anyone here ever done it?

what about a 9.3 x74r ? or would it be too long

It was original chamberd i 303
The length is possible the biggest issue.
Getting around the "bend" might be difficult.
The 577/450 MH round is extremly bottelnecked so thats no help.
How about the strength of the action, I know that the Martini action has been chambered i lot`s of different rounds also som rather hot ones.
Guess I just have to get hold of some rounds an do som testing.
9,3X74 is not a option, I have a 375H&H and 416Rigby so I dont need another medium bore.
One option si to chamber it in the original 577/450 but it is quite obsolete and quite anemic There is the issu of the cost the chamber reamer from Clymer cost $370 + shipping.
And getting hold of a barrel with the correct bore and groove dimensions is not easy.
Can use a 458 barrel but that will create a sort of "bastard" round.