... a friend of mine in the usa who got the billet box on the 1st sale and is thrilled with it was chatting with me this morning , i asked him if he could fit the AW 18350's in the bb , his answer was " That's what im using sahil " !! the 18350's fit like a glove . . .
Sahilm, I believe your friend is mistaken. There's no way that two 18350's will fit in the BB. There just isn't room.
I agree that it would be cool for some future "Bigger Billet Box" to support 18350's - and perhaps with the additional space created for those batteries, throw in a more versatile regulation circuit (like a DNAxx!).
But honestly battery life has not really been a problem with the BB as-is. I have not done any specific testing comparing the BB with my other (fairly popular model) stacked-16340 tube mods, but based on my experience so far I will venture to guess that the BB regulation is
slightly less efficient than that tube mod. With the tube mods, a battery swap out was usually required at the end of a work day; with the BB I usually have to swap out batteries mid-afternoon. Even so, the BB and spare set of batteries easily gets me through the entire day.