I have a new T/C Hawken-Renegade vernier tang sight, a No. 719 that I bought online about ten years ago for $29.50. I was going to put it on an Investarm Hawken but I would have to replace the front sight with something taller then the factory sight and have a hole drilled and threaded in the tang. I did buy a front sight that is 5/8 inch tall but I never did mount the sights. The base of the 719 sight is just under 1/2 inch wide and the screw holes are 1 and 1/4 inches apart. The directions say to use a #29 drill and a 8-32 tap. I hope this is helpful. I do not want to sell the sights.

Well the machine shop is not going to do the work for me. So I guess its a closed deal.

There is a lot of tang sights on ebay, most are fairly expensive. There is one that looks to be a T/C No. 719 that is bid at $26 presently.