Bushnell scopechief and Banner bullet drop comp

[Weldor]

I came into posession of 2 Bushnell scopes, both 3x9x40 japanese glass. Both have the old 3 or 4 bullet drop dials. I need to get a replacemnet top screw for one. (they are delron or nylon) .They seem to track relatively well. Anyone have info on these from person experience? I'm thinking a great 22lr or 22 mag with the write in turret?