This subject has been covered before and a search may be of help but I think the difference is in the barrel pin hole. I think the hole is larger on the aa frames and when you inlarge the hole on the barrel you are no longer able to use that barrel on the reg contenders, also believe that it has to be done by TC or a good gun smith. I think I have read where that is the only difference. Ladobe or david D will know for sure.
Deaconllb
