The PB Platinum 338 gr will do the job, if it will shoot in your Hawkin. The Platinum is suppose to hold up better than the std Powerbelt. I have killed several elk with the Powerbelt 340 gr HP ( I think it is discontinued now) that I pressed a 17 cal. air rifle pellet into the hollow point.
I am down to 80 gr, of BH209 in my inline, but you cannot use the 209 in the Hawkin Side lock. I'd recommend about 90 gr of Black Powder, not over 100. 777 and Pyrodex have habit of degrading. If you use either make sure to take a fresh container when you go hunting .
