Thank you for you replies.
Too light a load, if more powder will get a better burn I'll try stepping up to more powder. This is the bottom of the chart. New gun, new to me caliber, I thought I'd start right at the bottom and move up slowly. Kinda like all the books tell us but I can do it in big steps.
I'm using Federal Premium 210M primers. OAL 2.53" My reloading manual Shows a 300 grain jacketed bullet with 49.2 grains 4198 will produce a velocity of 2101 fps and a pressure of 29,900 psi. My Rolling Block is a Pedersoli, they spec their Rolling Block not to exceed pressure of 31,000 CUP/PSI. This rifle will handle all the max loads for the 1876 Springfield as well as 1886 Winchester and 1895 Marlin loads. The max loads for the Ruger Number 1 and Number 3 are beyond this guns Pressure limits. Now, the manual used a test barrel of 24" and has pressure in PSI, my rolling Block has a 30 inch barrel and Pedersoli lists the pressure in PSI/CUP. I may have to make changes to the load when using a 30"barrel rather than a 24" barrel, I don't know. I've not enough experience reloading to have learned that yet. I'm fairly new at this. As far as the pressure, Pederolsi just lists PSI and CUP as if it's the same measurement. I don't know about that either.
I didn't crimp these much as I have a single shot and didn't think I need to, but I'll crimp the next batch more.
4198 wasn't my first choice of powder for loading the 45-70 but it is the ONLY powder available to me that was listed in any load data I could find for this caliber. It was the only powder the only sporting good store within a 10 hour round trip from home had left and I bought the only two jars. If I don't use 4198 I don't shoot, until if and when the supply problems up here ever get rectified. I have about five pounds of H4350 that I use for loading 260 caliber for my precision rifle, but i could find no data for that powder in this caliber.
Pedersoli states their 40-60/45-90/45-110/45-120/50-70 and 50-90 Rolling blocks are made for black powder cartridges and has 'black powder only' stamped on the barrels, the 45-70 can be used with commercial smokeless cartridges or reloaded black powder or smokeless cartridges.
I couldn't use black powder if I wanted to, as there is none available around here. I've shot Rolling Blocks, Sharps and my Marlin lever with black powder. For now I think I'll just stick to smokeless with this gun and my 1889 Marlin. But I appreciate your suggestion.
Thanks again for the replies.