Intermittent Dropin, Surefire 6P

[lightfooted]

I wouldn't worry about it. The foil makes it work and also helps transfer heat to the head. All three of my Surefires have this treatment as it makes them reliable as far as contact issues go. Two of them are even old Solarforce drop-ins which were made specifically to fit in Surefire lights. I have noticed a difference in the dropins for their own branded lights which leads me to think someone might have made the adaption to your light because it was what they had but I kinda feel like if they knew enough to do the boring for an 18650...they should have known about the difference with the dropin. I used the aluminum tape from the hardware store to do the job, it's thicker than typical kitchen aluminum foil. I've not had an issue with it in the 6-7 years since first wrapping them.