I can make my 40-65 shoot up to 40-82speeds or down to 40-50 speeds using 3 different bullets and/or changing powders, 2f or 3f. I have loads for 200yd schuetzen, 2-500meter silhouette, and 800-900-1000yd creedmoor.
the cartridge on the right uses a micro-mini-goove bullet with reduced diameter bands on the first 3 to allow the bullet to seat out farther, giving room for 13 gr more powder.
A 45-70 can be loaded the same way up to 45-90 loads.
I haven't added up the cost lately, but a few years ago it cost me $8.00 to load 60 rounds, 1 days shooting.
BTW....These cartridges are made for and will perform the best with true bp.