Dixie sells the Quic-kee Mount in 2 sizes for 15/16th's and 1 inch barrels.
Theystatethat no drilling, tapping or hammer modificationis necessary.
http://www.dixiegunworks.com/product_info.php?products_id=7612
http://www.dixiegunworks.com/product_info.php?products_id=7613