I own one for about 35 years and I love it! It always shoots well and shot 240gr.to 270gr. with good accuracy. The hornady 265gr. is a rifle bullet the speer 270gr. is a pistol bullet Speer's spokeman said the 270gr.would work well in the 444 Marlin and it is accurate in my old 444 as for your setup well what works for you is it. My setup is weaver see thur mount and a weaver 3x9x38 it's sighted in at 50 yards. I shot both bullets 265gr. and 270gr. at 50 yards the accuracy was the same. If you are going for deer size game go with the 265gr, or 270gr.. I JUST READ THAT THE 444 MARLIN CAN BE HAND LOADED TO 405 WIN. level. good luck
