I currently shoot a Marlin 444SS in of course 444 Marlin.

I am interested in knowing if there is a wildcat out there to where I can keep the existing barrel and still have the cartridge work in this type of action?

Would like to see if I could get an honest 2500fps with 250gr. Nosler Partition.

It would be a new one I think. But the Marlin 336/444/1895 action can be modified to accept the 348 Winchester case (50 Alaskan). So a 348 Winchester necked up to accept the .429" bullet, case length 2.25", blow out the case to reduce taper, a .6" neck and 20 degree shoulder, alter the carrier and ejector so it will cycle a 2.7" cartridge, and you could probably get 2500 fps with the 250 grain Nosler.

Thanks Jackfish. The 450 Alaskan has proven itself I wonder why no one has considered trying in .44 caliber?

Shoot, if you are going to wildcat it -- go for the .50 alaskan!!

Spoor,
Get a hold of a 450Marlin case, take ur carbide 44Mag size die, and neck it down. RCBS.Load shows ~ 20% increased powder capacity.
Very little modification needed to the loading or ejection port to take the belted round. NOT so with the much larger rim of the 348 case.
Lol, I've got aforesaid round sitting here on my bench. No problem I reckin hitting 3500#'s.
Now for the reamer,,,,,,,,,,,, Dave Manson would be happy to make you one. www.mansonreamers.com. Prolly get away with a FL 450M die, set the shoulder back a tad with the 44Mag die, and fireform.
Cheers,
R*2

The 348 has the same rim as the 45/70. I would neck a 50AK down instead of necking a .348 up.

No need to anneal case necks and the 50 ak case will give more powder capacity unless you improve the 348 case by blowing out the shoulders.

Beartooth makes a great 405 grain cast bullet in .429, this wildcat should push it 2000-2100 fps with the right powder.