I did something similar when using an old Krag sporter. I used 130 grain flat point "30/30" bullet and a light load of 3031. It shot pretty good and feed alright. Your 150 grain bullets would have probably fed even better in my rifle, but each rifle is different, so try it for sure.
I put a new 35 caliber barrel on this same Krag and the mock cartridges would not feed. So I tried the old 130 grain bullets and they did not feed worth beans either. I had put a smaller chamfer/radius on the edge of the chamber. I fixed it by hand enlarging the radius on the left side.
If all goes well that is a good thing. If you have a valuable collectors item, I would think twice before doing any mods. It would be better then to find another bullet that works.