Martin Herrick is a very clever man as well as being a very nice chap. He found an original Giffard barrel for me, cleaned it up and sleeved it to .22 which i can now use in place of my Giffard's original 8mm barrel. Shooting with the .22 gives a consistent 10.5 ft/lbs with Gamo lead balls. He also modified a period aperture sight to fit on a modified stock bolt. There are some pictures of this under Giffard on the vintage airgun website. My lasting regret is that i did not buy some of his specials when they were offered to me at a very reasonable price years ago. He used to be on here as customstocker but i have now lost touch with him. Perhaps he could be pursuaded to knock out a batch of converted Martini Henrys. I'am sure there are a few of us on here who are drooling over this one.