Sight inserts for ERSisk
Ellis, here's a couple of links. You may have to drop a note and verify 'tunnel' diameters.
Lee Shaver
http://stores.leeshavergunsmithing.com/front-sight-insert-cards/
Buffalo Arms
http://www.buffaloarms.com/front_sight_insert_cards_pr-4083.aspx
Hope you can find what you need.