The answer looks like yes!
Simply take a multitool or some snips and trim the lip off the dewalt battery. it should now slide onto the drill.
yes this means that Dewalt fanboys can go ahead and buy the milwaukee cordless heat gun and not have to shell out for the batteries and charger, YAY!
Does the battery still fit in dewalt tools? Yes – and also the charger Duh
Will this invalidate my warranty? on the battery most certainly, on the milwaukee tool – Nope!
Will this fry my tool or kill me? I dont know.
What can i spend the money on that i save not having to buy the 19v milwaukee batteries and charger? Beer