45-70s have been made since 1873 or thereabouts. You can encounter all sorts of designs from weak to strong and can find rifles made out of all sorts of steel. Several writers, experimenters & the major loading manuals place 45-70 rifles into 3 or 4 categories. Cat. 1 rifles are the old ones; Trap Door Springfields, Peabodys, Remington (& other) Rolling Blocks, Side Hammer Sharps, 1881 Marlins, Ballards and the like. Those are OK for black powder & lead bullets or maybe light loads of smokeless. Cat. 2 rifles are a bit stronger. Those are original Sharps-Borchards, 1886 Winchesters, the case-hardened 1885 Winchesters, Remington-Lees, etc. Original 1895 Marlins probably go into this category. You can pour a bit more smokeless into those. Cat. 3 rifles are even stronger. Some writers put original 1885 Winchesters with blued actions into this category, but others disagree. Presumably the new Marlin 1895 rifles are Category 3, as are new made Winchesters, Sharps-Borchardts, etc. If there is a Category 4, it is probably limited to Rugers, converted Siamese Mausers, and the lesser-known single shots similar to Rugers. I guess those are "modern" rifles.
