the duo mount system is kinda an odd duck. i have one for my new englander but havent installed it . i called thompson center and they told me that it has some problems with returning the scope to zero after puting it back off and on but maybe some others have an opinion. i would personaly go with a standard set ofbases andrings that releaseif it were me. the duo ring system is actually 3 parts . the base, the adapter ,and the rings,.