These will work
Warne Maxima 1-Piece Steel Weaver-Style Scope Base, Thompson Center Contender
Redfield Scope Base with 1" Standard Rings Thompson Center Contender (mount it backwards, fine for that amount of recoil, don't need all 3 rings)
Stratton Custom TC Accessories Weaver-Style Steel 6-Hole Scope Base Thompson Center Contender (a little pricey, you don't need all 6 holes on a 223, but a great product)
Hope this helps.