Very nice DrLava...I am glad you got "into" open cans.... ;D The barrel looks great, but I will be using mine for a blu-ray as I am doing the MXDL mod with my "hot" open can diode. I agree the picture does not do the beam justice. I was comparing my SenTorch against my open can and the open can beam looks tighter. I know the SenTorch also uses a glass lens. It's hard to explain but I think the beam specs of the open cans are better than closed can diodes. I sure wish we could find a data sheet for open cans.
I got my snap ring at a local auto store. I think it is the 3/4 " interior snap ring - not exterior and I got 3 sizes to find what fits best. Snap ring pliers work good for me on this. I shortened the battery spring by ~0.200" to relieve pressure. The "wings" on the switch may need to be opened a bit for good contact.
Mine is AA++ fit all the way.