Originally Posted by
Scharfschuetze
With the 1885 and no need to limit your overall length, you can seat the bullet so that it is touching the lead or start of the rifling. This will probably give you more initial build up of pressure than crimping.
4198 is on the fast side of rifle powders and is a pretty good powder for the 45/70. I've used it a bit in the 45/70 with 405 grain bullets and haven't had any overly dirty barrels. At 39 grains of 4198, I'll bet you are closer to 1,700 fps than 1,500 fps. Have you chronographed the load?