I'm replying without having first read through the other replies. Back in the mid-'80s, I bought my first Marlin 1895 (of five), the SS model with Microgroove rifling. Using the then-current edition of the Speer reloading manual, I worked up to 53 gr. of IMR-3031 shown as maximum for lever-actions for the Speer 400 gr. JFP, with Remington and Winchester brass and CCI-200 primers. The same load worked fine with bullets I cast with Lyman no. 2 alloy from the RCBS 45-405-GC mould. Both loads filled the cases to a level requiring slight compression of the powder when seating the bullet----with no room or need for a filler. Contrary to whatever belief that cast bullets do not work with Microgroove rifling, casting with a hard alloy, using a gas check, and sizing to .458" or .459" (for rifling with '.457" groove diameter) will result in little to no leading of the bore even with heavy safe loads. Back then, I used the Lyman Ideal bullet lube, but later switched to moly. Either load does the job on wild hogs in the Everglades.Hi, I’m going to reload some 45-70 for my sharps and my marlin 45-70 using IMR 3031. My question revolves around using a filler of some sort, my background in reloading stems over 30 years but this is my second attempt at loading the 45-70. First was with black powder which of course filled the case. But now that I have the marlin I want a load that I can shoot in both. I’ve heard the marlin doesn’t like BP
So I like any thoughts and suggestions on loads and using fillers and what filler to use.