DOA but with the hammer spur?
 

I'm wondering how that works, double-action only but with a hammer spur. Does it simply not pull back, or will it discharge the round when you let it go?

I know on SIG DAK trigger you cant pull hammer back manally, and need to pull trigger for hammer to move.

My CZ-38 is an external hammer DAO. You can pull back the hammer but it just falls back down. Whether it does with enough force to set off a round I don't know, and have no intention of finding out.