Looking for the best load data for 300 blackout using unique powder.
150g Speer grand slam.
Thanks in advanced.
Maybe you could clarify what you're looking for exactly. With that combo, I'm guessing subsonic loads, and hopefully in a bolt action or single shot? That would be a really poor combo in either supersonic loads or a semi-auto.
If you're looking for a quiet subsonic load, that combo will work fine, but you're going to need to work down a load for your barrel. Notice I said "work down"; do not attempt to work "up" for subsonic loads, especially with jacketed bullets. Sticking a bullet in the barrel is no fun. You may end up anywhere between 5-7 grains Unique with that bullet; start on the high end and work down to 1000-1030 fps.