It depends on the production, but ever since Brandon Lee got killed on the set of The Crow, there's been a definite move away from the "real guns on set" style

Now there's supposed to be very strict rules on when and where you can use real guns vs. prop guns and everything is supposed to be clearly marked and handled properly

From what I read about the situation, the producers literally did not give a shit

The armorer not being union was literally the least of the worst things they did, because there's talk of the weapons cage being open for anyone to just walk into, producers fucking around with the guns themselves and having themselves impromptu shooting sessions, everything just being unmarked and tossed around in buckets with no labels

It's honestly appalling on so many levels