Regardless of new Marlins being made in 444 or not, the ammo and nrass will not dry up overnight, maybe not for decades, many contender , encore ., NEF/H&R, rifles and barrels have been and will continue to be made, plus the myriad of wildcat and custom cartridges formed fro the 444 insure that someone will supply brass for years to come, there are also other cases that can be reworked to 444 as well, FEAR NOT!
