Using C to M adapter on a 26650 body and these head (without body) and installed 3853 module/reflector, you will get what you want if it's to use potted bulb.
You can also use C to M then M to D adapter with M*g D head and bi-focal reflector.
What is purpose of using large size head on 26650 body? Is it for LED or incan use? Is it for single cell?
It's for a LED with a single cell 26650 body I got from you about 2 weeks ago. I'm trying to fit a DBS head on there If possible. Do you have an adaptor for that? Thanks