I can't find a load that shoots in this gun using 150 gr. bullets

You may have to try some other bullet weights. I have never tried 150 grain bullets in my 300 WSM. I have had great success getting good groups with the 300 WSM using bullets of 165 to 180 grains.

My Remington rifle shoots quite well with H 4350 or IMR 4831 with either 180 grain Nosler Partitions or 180 grain Sierras. It also does well with H 4350 when shooting the 165 Nosler Accubond or 168 Barnes TSX.

THANKS I'LL PROBABLY HAVE TO TRY SOME 165'S