Tromix Lead Delivery Systems has published on their social media pages images of one of the prototype guns that they have been experimenting with back in 2007. They converted a Saiga-410 shotgun into a rifle chambered in .444 Marlin.
According to Tromix, the .444 Marlin rounds fit both the box magazines and 30 round drums.
Saiga-410 shotguns are chambered for 3″ shells of 410 Bore ammunition. That being said, the .444 Marlin will fit in Saiga-410 magazines lengthwise because the maximum overall length of .444 Marlin is 2.57″. The rim and case body dimensions are also similar. 410 Bore and .444 Marlin have .535 and .514 rim diameters and .481 and .470 base diameters respectively. So the similarities in the dimensions make the .444 Marlin fit the magazines of Saiga-410 shotguns without a need to modify the magazines. That was probably the reason why they chose to convert the Saiga-410 into a .444 Marlin rifle.
According to SAAMI specifications, the maximum average pressure (MAP) of 3″ .410 Bore shells is 13,500 psi whereas the .444 Marlin operates at about three times higher pressures having a SAAMI MAP of 42,000 psi. Tromix probably used a different, stronger bolt and front trunnion.
This is a really cool project which converts a 410 shotgun into a gun that shoots a cartridge performing like a .44 Magnum on steroids by launching .44 caliber 240-grain pills at 2,400 fps of muzzle velocity or 300-grain bullets at 2,000 fps. However, according to Tromix, there were feeding reliability issues with some factory cartridges loaded to shorter overall length. That was the reason they dropped the project.
Tromix has published these images as the first installment of their social media series called “Throw Back Thursday” where they show their prototype firearms that for whatever reason didn’t become production models. We will keep our readers posted on the most interesting Tromix prototype firearms.