Actual this is very good judging by those excellant pics I would say thats about as hard as you can push them and get good results !00 gr of Pyrodex [in how long a barrel?] or 80 gr of 777 and a 295gr PB.
I have friends that believe in them strongly the hunt brush and hardly ever shoot more than 50 yd they use 70 gr of 777 and the other one uses 85 gr RS one shoots an Apex the other a Rem. 700 and they have real good results too. I tried the 245 gr with 150 gr because thats what shoot accurate out of the Omega and they blow like a varmit bullet.
It looks to me like if your gun will shoot the heavy Pb's with a light to med. powder charge you can make them work alright. Lee