The maximum I can push cast bullets in my Marlin 336 is 1600 fps, then the group blows. So a plated bullet at 1500 fps is not exactly an improvement. The 30-30 is not a magnum cartridge by any means, and if you want your 150 grain bullet to shoot to point of impact, you need to get the velocity up closer to factory jacketed. This is what I got with factory 150 Core Lokt's.
Marlin M336 microgroove barrel,
150 gr Core-Lokt SP Remington Factory
29 Dec 2011 T = 56 °F
Ave Vel = 2253
Std Dev = 13
ES = 31
High = 2268
Low = 2237
N = 7