I load 5.0 gr Unique under the Hornady 147 gr XTP. About 1100 fps from the Glock 17. It must be in the +P range.
Considering jacketed gives more friction than coated lead, you might get there safely, but good idea to start lower and use a chrono. If you are getting over 1050 fps, you are probably going to be getting close to the sensible top end.
I know Buffalo bore loads a 147gr lead to 1175 fps, but no idea what powder they are using.
The 3 gr extra weight shouldn't make a whole lot of difference, but the lead bullet might be longer if it has a lube groove. I've seen some coated bullets that were cast from a non-grooved mold, so depending on your 150s, it might be a factor.
