Wa-HOO! That's some mighty fine iron sight shooting Cayugad. I'm glad they worked for you. They take a harder whack on the short starter than do the .570's, but they shoot straight out of my GM barrel too. You're right about those 1:70 twist GM barrels. I don't know how they could shoot any better (heavy though). I sure hope I get a chance to put one of those balls through a deer this fall.