I have an XHaler, not a Silver Bullet, but I imagine you are fine with 17670. It's 3.7V, so I don't see any reason damage would occur, as 18650 are 3.6V. Perhaps someone else knows of potential problems with the discharge rate vs that battery, in which case there would be damage to the battery first...otherwise I don't see a 0.1V difference in rating would matter.