I have had terrible luck with the microgroove rifling I my 45-70s. I had a friend gift me some great boolits in may weights and could find no accurate loads in any of them except for a couple hundred cast with a Lyman 457 122 hollow point mould. They shot great. So I bought one of those and they still shoot good out of my Ballard rifled gun that a got a couple months ago. And happily the other boolits he gave me also work just fine in the newer gun. He gave me 90 lbs or so and I think I am fixed for life. He also gave me another 80 lbs of 38 and 40 cal cast sized lubed boolits that I guess I will have to remelt into other calibers as I don't have a 38-55 or any 40 cal rifle..and will not get one anyway.. I did check the size of the boolits and the 45s measured 458..I did try drilling the base of some of the 405 gr bullets to make a hollow base(approx. 3/8 inch). Worked in the microgroove but too much trouble. BTW I also like the 5744 powder and I have quite a bit as I also use it in my Savage smokeless powder muzzleloader. Another great shooter. I also use 4198 and Reloader 7 will try some H335 as I have 20 lbs or so of it