Yes, with the adapter you're looking at another .25 of a inch. It's a great size, but a poor design.
I agree. Great size, love the stacked donut texture, but would have preferred it not have an adapter and be compatible with e-series tail caps. Maybe with the "spring tunnel" like Surefires have.
Basically the one Malkoff thing I am not super happy with. It works, but even with a good battery a hard enough bump will cause it to lose connection and if you have a multi mode head it can change modes.
Haven't had any issue with single mode heads, so it isn't really a huge issue. But removing the adapter is irritating. Kinda want to pick the head you will use on it and that is the end of the story. Except that isn't how it goes in practice, not in my world anyway. A pair of scissors or the back of a knife blade make good "wrenches" for the adapter. It is an interesting design, and as far as an adapter a good one, but the adapter is annoying.