Hello all. I've been loading for my 45-70 with the 32" BC barrel. I've been using 60gr of H4198 with 300gr Hornady hollow points which is top load according to the Hodgdon manual for the Marlin guns, observe, it is the load on the bottom of the left column, not the circled one. Sorry about the size, you may have to zoom in a bit on the pic to read it:
This load is stout but I like it. Shoots 1.25" groups at 100 yards and does a number on bowling balls! I have the barrel on my 270 action with the synthetic stock with a sock full of 8 shot in it, works great for dampening recoil. Only a big "push" not a sharp crack like necked-down cartridges. My question is this: what would the expected increase in velocity be due to the 32" barrel? I know that Tim has been working with 4198 and getting "diminishing returns". I have read on other forums that a 150-200 fps gain can be expected. What are some of the experiences here? According to the pic on this post this load measured 2424fps from a 24" barrel. Any input fellas or should I just go drop the cash and get a chrony?