Attaching a breech lock fd lens

[tayproductions]

I was given 3 Breech lock canon fd lenses. Two work fine with the adapter. The 50 mm will not "twist" all the way. It will mount and I Can open the aperture fully, but it only closes about half way. It works fine on the original F1 camera. Any suggestions?

 

[sn66p]

I'm no expert, but I had the same situation. Canon fd glass using a fotodiox adapter. I noted the older silver ringed lens do not tighten all the way down like the "new fd" glass. The aperture seemed to work just fine tho. End friction was tight.