32" compared to 24" in 45-70 with 4198?

[mattparliament]

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?  Also, anybody use the Barnes 250 gr. x-bullet in their 45-70?

[oso45-70]

Matt

I don't know what kind of velocity you are getting but there has to a gain with the longer barrel. I would think you have gained over a hundred FPS
if not more, I don't have a long barreled 45-70 now, All of mine are two GGs and a cowboy, I did have 1886 but never tryed loading it hot. With 60 grs H4198 you are smoking them down range. Sounds like one heck of a shooter. Good luck, Maybe some one will come on with some help. Good luck.......joe............