Known by many, explained by few. It's probably just me (but Lord knows I try), but I can't find any clarification on the "double tap" shot that charge weapons can produce. Does anyone know why we can fire immediately again after a charged shot is released? I do what I can to help people understand this game, but it helps if I do.
Thanks in advance.
What? you still try to teach how to play this game? 
Thought your are completely addicted to Isaac. 
Due to you question:
When take the Venom for example, you can fire uncharged shots with fixed rate fire, or a certain delay between the you shoot again.
The delay between a charged shot and an uncharged shot seems to be the same, but for the charged shot the delay timer seems to start, when you push the trigger to charge up your first shot.
That's for sure the same reason, why the charge mechanism doesn't break Tech Cloak while releasing the shot, but by charging the shot.
[edit]: oh, seems that is the same what TheNightSlasher said. I should wait that long with pressing the post button.