OK, latest update (head scratching). I loaded up several charges and shot them at 60 yards. I tried 34 grains IMR 4198 (going down) it shot horrible. Maybe a 10" group. Then I tried hotter loads going half-grain from 41.5 up to 43. The 3-shot groups were so incredibly sprayed, you would think it impossible. I could be more accurate with a sling shot. Some were 18" groups. (BTW, I gave the rifle a good thorough cleaning prior to this). These are cast 405 grain bullets I bought at the store.
So, I also had some other bullets I was able to buy recently. They are also 405 grain. Same shape. They are polymer coated measuring .457. I dumped 40 grains of 4198 under them. The results are in the attached pic. I am greatly relieved it isn't the rifle. I need to bring the sight over a bit, but at least they are together. Two in one hole and one next to it. So you guys were right that it is the bullets. Had these polymer bullets not shot well, I would have considered this rifle to be a wall hanger. But those bullets were the same shape and same weight. So how do you know you are getting good bullets when you find some?
We are going to try to shoot those other bullets in my son's gun to see if they shoot better in his. Assuming they don't (likely) is there anything I can do to make them shoot better? They do not have a place for a gas check on the back. Obviously, it is not the powder charge.
Les, read my post, #11, gives you a lot of data on reloading for the 45-70. Rim Rock bullets makes the bullets that Buffalo Bore uses to make their hot loads; 20 or 22 Brinell. Right now there's a waiting period for their bullets, 2-3 weeks, but they are a good company to do business with, very conscientious and....they actually answer the telephone. Personally I would never shoot cast bullets in a rifle unless that bullet has a gas check on the back of it. The gas check helps to make a good seal against the rifling, plus it helps to keep the hot gases away from the base of the bullet to prevent leading. And...if you are looking for "hot" loads, cast bullets (in my opinion) are not the way to go. Accuracy yes, speed not a good idea because you will reach a point where there's leading, and....if you do not notice the leading it could lead to a catastrophic failure of your rifle. And....even if you do notice the leading before there is/was a problem it is a real "PITA' to scrub that lead out of the barrel. Ask me how I know!!!????? I'm glad that you tried a different bullet and got good results. These Marlin 1895s are good shooting rifles, whether the are "JMs" or not, they shoot. Also important to remember that OAL and case overall length is defined by the cannular groove in the bullet, not by what your loading manual has in it, unless that bullet is made by the same manufacturer as the bullet being used like a Hornady manual for instance. The only reason for writing this is that the cannular groove for cast bullets will vary greatly dependent upon the mold/s that are being used. Also one last thing if you don't have one I strongly suggest that you get a Lee Factory Crimp die. I read about this in another post on the forum here. I bought one (like $12) the best thing I ever did. The crimps are like factory crimps, the dies are easy to set up and they also save brass because the die has a collet that actually crimps the casing into the cannular instead of rolling the brass into the cannular.