[bubbatime]

1) 123 batteries last for 10 plus years without a charge. They are super reliable.
2) 123 batteries do not have circuit protection built into them that turns the battery off. A good thing to have on a weapon light. Less parts to fail, the better.
3) 123 batteries fit more lights

You see where I'm gong with this? The only reason I would put 18650 batteries in a weapon mounted light, was for training purposes or night time hunting. If you do a LOT of night time training, then I can see have a rechargeable battery, to save money. If you do a LOT of night time hunting, then I can see having a rechargeable battery, to save money. If these two scenarios don't apply to you, then why not just stick with the tried and true, ultra reliable, long lasting, 123 batteries?

And realistically, how much use is a weapon light going to see every year? 5 minutes use per year? At best? You stick the weapon in the corner by your bed and forget about it. Change your batteries every 5 years and you STILL have super fresh lithium batteries.

I have probably 8 rifles/shotguns/handguns with weapon mounted lights, and they ALL use 123 batteries. I am a big proponent of weapon mounted lights. And also a big proponent of using primary lithium 123 batteries in them.

For flashlight mounts, look at Impact Weapon Components and Arisaka Defense... these two companies make some of the best flashlight mounts in the industry, in my opinion.

 

[bubbatime]

And just fyi, for your two cell lights that take 123 batteries but won't fit a 18650, a 16650 battery will fit and work. It's just the smaller version of an 18650.

16650 KeepPower 2500mAh Sanyo UR16650ZTA 4.20V Protected Button Top