The .444 Marlin factory ammo uses pistol bullets, that's how it was born. It used the same jacketed pistol bullets as the .44, etc...That is the main knock against the .444, those jacketed pistol bullets are too short and soft to provide knockdown and penetration on big game, that has not been my observations however. i think that the bullets you saw are swaged lead, if so, you should not load them higher then 800fps. or your bore will lead. Hardcast bullets work better, and can be used right up to 2200fps. depending on weight, I use the Chambers 290 Gr LFN PB and the 325gr.Chambers WFN GC in these rifles for max. penetration and knockdown.