Hi jcdflint,
Yes, I have the 1" GM drop-in .62 smoothie barrel mounted in a T/C renegade stock. It took a little inletting to fit exactly as I wanted but not much. It performs wonderfully with shot. With just a little tweeking, I use Roundball's formula for a paper shot cup, wonder wads and #6 shot. I have given the squirrels fits with it and even made a few modern shotgunners jealous.
I am very confident with it as I intend to go get a turkey with it this spring.
It also shoots roundballs decent out to 50 yards,
DanL