In college I would rep skullcrushers with as much as 265lbs on a cambered bar for 4-6 reps.....back then I know I could've done more, but I was scared to go for more. I trained alone a lot.
Today I still throw up 225-235lbs for skullcrushers for as many 12 reps.
I've only seen less than a hanful of fellas in my life across all gyms I've trained at that can keep up with me on arm strength.