Bobby said 90(ish) it's what he shoots when hunting elk . He states that it's more forgiving of different loads. The above was the first time out (I need more range time to try sw 2f,3f at 80)and had to work on son's flinter 1st, before sending it to him. He said 70grns for target/80 for hunting, he shoots swiss. For elk Bobby Hoyt likes the lyman great plains bullets in 54(if you can find them)
I tried 3 Black belts left over from the early 2000s 54 405grns in my son's gun, 2 at 50 within an inch the other no ware near, the plastic scert might have failed.