what sights should i use

[inkt4life]

I have looked all over trying to find sights to put on my dads H&R single shot that he wants to use for deer and possibly for turkey, the problem i am having is that it seems all of the sights i am finding are for a vent ribbed shotgun or needs to have an existing dovetail. I know i am going to have to drill and tap to put sights on but i cannot find any sights for a regular barrel 12 gauge, any suggestions would be greatly appreiciated