Just propane. Semi-auto only (Should have clarified that, sorry)
I found that I could get close to if not a full mag out of a single fill if I kept them in my pant pockets before I used them opposed to the pouches on my plate carrier. Next time I'll tape hand warmers to the mags :P
Yesterday's tears are today's wounds
Today's wounds are tomorrows scars
Tomorrows scars are your life's war cry...
-Fuck 'em up Gentlemen