Cast levergun loads for the 450 Marlin are hard to obtain. I mean realistic, safe loads using 400gr slugs. You can't use 45-70 info, that round has a larger case volume than the 450 so top loads are unsafe. The Lyman data book contains loads for the 450 but the sidebar notes that they used a "universal receiver" for the tests, not a levergun so I figure the date isn't reliable. Also, it's difficult to compare any data between 45-70 and 450 as the former is given in CUP while the later is posted in PSI. I won't go into how it happened but I ended up loading some 400gr loads at the top end using SR4759. These produce over 40,000 PSI but the accuracy is amazing all the way out at the 200yd mark. So the question is, what do other 450 shooters use for a mid to heavy loads? Just as a final note the 1895M is, in my opinion, the best hunting arm ever. Carrying, pointing, rapid fire and the ability to place "brown on the ground" right now is superb and I grew up hating lever guns.