H&R won't fit a .444 barrel to a frame made prior to '99, if that means anything to ya, they changed the heat treating on the late model frames, all of the * marked barrels on the accessory list can't be fitted to older frames, the .444 is one of em.
Spanky, that's how the .444 came about, but the chambers are different diameters, the 445 Supermag is a popular self rechamber for the 44mag.
Ammoguide's description on the .444....
The .444 Marlin was introduced in 1964 in the Marlin Model 336 lever-action rifle.
In the late 1950's, early 1960's, the .44 Magnum was experiencing moderate success in short, light lever-action rifle chamberings. However, hunters were soon asking for more power than the handgun-based round could provide. Marlin's answer was to fundamentally stretch the .44 Magnum case to provide over twice the powder capacity.
The result is a cartridge that shoots the same 240 grain .429-inch bullets as the .44 Magnum, at a nominal 500 fps faster muzzle velocity. However, due to it's low sectional density characteristics, the standard 240 grain bullet is not suitable for game larger than whitetail deer. Such applications are best left to more modern 265 and 300 grain bullets specifically developed for larger North American game.
Maximum working pressure for the .444 Marlin is 44,000 c.u.p. with maximum product average pressure of 47.200 c.u.p. The 240 grain bullet exits the Model 336 at 2350 fps and 2930 ft-lbs of energy.
Tim
http://ammoguide.com/?catid=42http://ammoguide.com/?catid=43http://ammoguide.com/?catid=191
