Yeah, lots of productions use airsoft in place of blank firers for various reasons. Be it cost, safety etc. You can generally tell because it looks absolute shite. They often don't bother to simulate case ejection and muzzle flashes look like crap. Though it can be done fairly well if people know what they're doing. I seem to recall Stargate SG-1 looking pretty OK for the time.
Imo, no dummy/airsoft guns will ever replace proper blank firing adapted guns on screen. They just don't have the presence. Imagine Heat shot with airsoft guns. It just wouldn't have the same impact.
Anyway, regarding Alec Baldwin being a murderer, lots of rumours circulating it was an actual firearm with a live round. Quite what the fuck live rounds and non blank fire adapted firearms are doing on a film set, I don't know. I'm hearing lots of reports of staff walking out over safety concerns in general as well as firearms safety concerns from previous incidents on set. I gather some of these staff were replaced with people that were perhaps not qualified to replace who they did. Whatever happened, it's a big shit show and some people are going to be in a lot of trouble.
Perhaps if Baldwin wasn't so rabidly anti gun, he might know the basics of firearms safety...I couldn't imagine pointing even a blank firer at someone I wasn't willing to injure.
Though the memes coming out of this are quite entertaining. (At Baldwin's expense of course. Not the poor people he shot)