Awesome low pressure cartridges?

[Dukeoflawnchair]

I'm looking at sourcing a nitro proofed butchered Martini Enfield and rebarreling it to caliber.

Trying to be conservative and keep pressures below .303 cordite ball mk I pressures. (Below 46000 MAP PSI)

So far, two options are the 405 Winchester (rimmed) or a 338 Marlin Express if I figure out a mod for extraction. 444 or 4570 are options as well, I suppose.

Any other suggestions that come to mind for anyone?

Has anyone else done this genre of tinkering?

Many thanks!

 

[c-fbmi]

303 Brit, 375 Flanged 2.5", 45-90, 45-110, 35 Win, 50-110 Win...........smaller stuff...25-35, 25-20, 32-20, 32-40, 38-55, 348 Win even the old 30-30 or 32 Spl, 30-40 Krag, 357 Maximum, 357 Herrett...........the list is pretty much endless..........

 

[vagrantviking]

There's a limit on the length/diameter of cartridge the martini action can handle.
45-90 with short bullets might work but would be getting to the limit. I had one in 45-70 and loading with long fat bullets was almost too much.
Currently have one in 22k hornet and it's a pain trying to drop the little shell into a chamber with a scope blocking most of the action opening.

Personally I would look at something that would have been traditional in the old days of British cartridges. Take a look in Cartridges of the World or some forums from over the pond.
Really depends on what you want it to do....

 

[trevj]

38-55 can be made from blown out 30-30 brass, even if it's a bit short.

40-65 has nice taper to it, as do a couple less common BP cartridges, if getting the case around the corner is an issue.

Cheers
Trev

 

[Blastattack]

Keep in mind that force is a function of both pressure and area. Reducing the area that the pressure has to work on is just as effective as reducing the pressure alone. Slimmer cartridges can be loaded pretty hotly without increasing the force applied to the action (compared to .303 for example).

For example, a .22 K-hornet at 100000 psi puts less stress on the action than a .300 WM at 43000 PSI, using absolutely worst case scenario measurements. In reality the difference would be even larger.