I shoot 45-70 in both a 95 Marlin Rifle length lever action and a NEF Handy Rifle. The Handy is very painful to shoot in 45-70 even with light loads and light bullets. I make a trip to Alaska every year for a couple of weeks and the 45-70 is my mainstay for a rifle. Over the years I have talked with numerous hunters and guides and they universally say that a big hard cast bullet in the 45-70 is what they prefer for all the big game they come up against in Alaska. Most of my plinking is with 330 grain hard cast bullets, and the bullet I use for Alaska in the 405 grain round nose flat point hard cast bullet. I have been shooting 55 grains of IMR-4198 behind the 330 grain bullet and 50 grains of IMR-4198 benind the 405 grain bullet. (Standard large rifle primers in both..) Those are safe in my 1895ss rifle but I started about 10%down and worked up looking for accuracy and pressure signs. Your TC Rifle should be somewhat stronger than my lever gun. I would never shoot any of the above loads in my handy rifle. I tend to stay with loads published for the old trapdoor springfields for it as they don't abuse you quite as much. Good luck with the load development. Blitzfike
