[FrankenMauser]

.444 Marlin is a pretty decent, if unloved, cartridge.

But, if you don't reload, it's very nearly a dead end (and not cheap to shoot).
There are essentially only 3 semi-affordable factory loads on the market:
Remington 240 gr SP @ 2,350 fps (underwhelming, a handgun bullet, and $40-50 / box)
Hornady LeveRevolution 265 gr FTX @ 2,325 fps (short cases, not ideal if saving brass for a reloader or to reload it yourself, disappointing bullet, $30-40 / box)
Hornady Superformance 265 gr FP Interlock @ 2,400 fps (great load, great bullet, good brass, $30-45 / box)

Cor-Bon, Buffalo Bore, and Grizzly Ammunition do offer "niche" loads for .444 Marlin, but they're even more expensive.


If you were to reload, 'standard' specs are generally in the ball park of:
200 gr bullet @ 2,300 fps to 2,600 fps (depending on bullet design and how hot it's loaded)
240 gr bullet @ 2,200 fps to 2,500 fps (depending on bullet design and how hot it's loaded)

265 gr bullet @ 2,200 fps to 2,300 fps (moderate handloads)
265 gr bullet @ 2,400 fps (hot handloads or Hornady Superformance factory ammo)

300 gr bullet @ 1,900 fps to 2,100 fps (moderate to hot handloads)



Drawbacks of .444 Marlin:
Factory ammo can be difficult to find locally.

Remington only runs their .444 Marlin load as a "seasonal run" cartridge. That means they don't make it unless they have more than 125,000 rounds ordered through distributors/dealers, and they only make it when they have machinery available. So, if the demand isn't there... you may not see that ammunition for a year, or more.

It has an extremely short throat for a rifle cartridge. If reloading - Even if your magazine length might let you 'load long' with the bullets farther out of the case, your throat isn't going to allow it. You'll have to stick to the standard overall length, or pay for some one to do some throat work to the rifle.

Most of the .429/.430/.431 bullets on the market are designed for handgun velocities and have cannelures for .44 Special and/or .44 Mag. Neither concept works well for .444 Marlin. (Though, the velocity issue doesn't matter, if you're only punching paper.)

If reloading - Brass is only run once a year (or every 2 years) by Remington. When the supply starts to dry up, it gets into the $1 / case price range ($90-105 per 100 cases). Hornady brass is better (my opinion), but it runs about $90 per 100 cases, year-round. So... brass isn't cheap.

Bullet trajectories suck. Most bullets appropriate for use in .444 Marlin have the ballistic coefficient of a brick. They shed velocity like there's no tomorrow, and drop like a rock brick.



If I were considering other cartridges, I'd be giving 7.62x54R and .30-40 Krag serious thought.
BUT... .30-40 Krag has it's own availability issues (see the "seasonal run" reference above) ... except .30-40 is run even less frequently, there are only two loads on the market, and Winchester (the other load) only runs .30-40 Krag ammunition about every 2-3 years.

I really like my .444 Marlin and I loved my .30-40 Krag, but ammunition and component availability can be serious issues. If I eliminate the component (reloading) option, and have to stick with just factory ammo.... I wouldn't be considering either of them for the project.