I'm not sure it can't shoot BH 209 The manual says the gun can shoot 150gr of T7.
So, I would think 80-100gr of BH would be fine.
Shack...The gun has a Green Mountain barrel, and Timney trigger. It should be a great shooter.
The new model is called the Big Horn. It's basically a Wolverine with a longer 26" barrel. Yours probably has a 22".
I'm not expert on the gun, but I just got one, and am still learning about it.
Sabotloader knows the gun well.