Oldtimr, I would use FMJ practically for the penetration that you would get for it to go through the shoulder plate. I get that a rifle will work better, and my 30-06 is my primary hunting firearm. I got a 10mm to have as a sidearm in case they are too close for a rifle shot or getting charged close through the woods when a rifle wouldn't be ideal. I just need a round for my 10mm that can do the job if needed, and a hard cast load isn't something I can shoot through my stock glock barrel.