Track has it, threaded for the eyepiece, which you have to buy seperately. I have one, but I've yet to put it on a rifle. Most of my rifles are PC
flint and I can't convince myself to put it on that kind of rifle. Once those screw holes are drilled on a custom gun, the game is over. My humble opinion, ofcourse. This creates a dilema for me because my bifocal needy eyes don't like open sights. I've tried, rejected and gone back to
a Merit eyepiece which works fine for target work, but is less than ideal for hunting. I'm thinking of making some sort of sight mounting bracket that mounts to the rifle using the lock bolts and cantilevers over/on the breech area, sort of similar to what Weaver did way back as scope mount for Remington shotguns, but with some sort of simple peep instead. I think this might
work ok, especially on a rifle with two lock bolts. It would require longer bolts, but would be easy to mount and remove and would not "damage"
the barrel. It may work on rifles with a single lock bolt(like most of mine)as long as the bracket makes contact with the top barrel flat, to prevent wobble, perhaps with a layer of moleskin in between to protect the barrel finish.