The under hammer "Rosie" is one I assembled from a Green Mtn. barrel I found in WI, an Allen breech/trigger mechanism, unusual dark striped maple stock and a tang sight set I have had for years. It shoots 540 grain grease groove bullets that are bore dia., .060 fiber wads, 80 grains of Goex FFG and fired off with a 209 shotgun primer. The other day I wanted to make sure that the sight is repeatable so I shot a few at 100 yards, then out to 200 yards and finally at 300 yards. I use a home made 8.5 x 11 bright paper backer made into home made "shoot-n-see" with a 4 inch bull in the center. at 100 and 200 most all shots go into the bull and at 300 all go into the overall target. I was shooting off cross sticks. Here's a picture.
