Has anyone who uses a Solarforce L2 variation P6 tried using a 20700 size battery in it? The 18650 battery in my Solarforce flashlights rattle a little. I was wondering if the 20700 would fit in the tube? I have an Xtar 18700 battery and it fits length wise but I’m wondering if the 20700 with it’s larger capacity could squeeze in and not make the rattling sound. Has anyone tried this experiment? Thanks.
No, it won’t fit. Not even close.
Doubt that very much. The classic Surefire lights were designed for CR123A primaries. They had a bore of app 16.5mm. But those Surefires were “meaty” enough to be bored out to app. 18.65mm with enough strenght left. You can do that yourself. All you need is a reamer and a “bit” of elbow grease.
Then came SolarForce with series of lights that did not need to be bored out. Don’t own any of those lights myself but I think that your “rattle” is caused by about 0.5mm play. An XTAR 18700 isn’t what you may call a skinny battery, but I think you need at least 1.5mm more room to fit in a 20700. Don’t know if SolarForce lights are that meaty.
They won’t fit, I just took this picture:
However, the SF tubes are meaty enough to make it work. You only need 1.5 mm increase in diameter as a rough estimate. At the skinniest part of the tube ( near/above/around the threads), the required material should be available.
I would use a “brake hone” or similar to make it work.
22.00-2*(0.68)=20.64mm. This is threads is size. I dont think you can leave thickness less than 0.3mm, so actual size that can be bored is near 20.04 max. Dont think you will find 20700 cell that will fit this size.
Thanks, kiriba-ru. I trust your experience and calculation more than my caliper estimate.
I guess it won’t work then! 
I want to thank everyone for their contributions. I agree it won’t fit which is a disappointment. The vaping industry has really added a number of new more powerful batteries and I was hoping to take advantage of these new cells.