The best thing you could ever do is get a permit to fire blanks. This will be useful when people who hear gunshots call the police and they will already know what's going on. If your location person (or YOU) goes around to the neighbors and lets them know what's going on, no one will freak out. Cover all your bases. Next, hire a professional gun guy or prop guy to do the gunfire. Trust me. There's a specific protocol we adhere to when handling firearms. Keep in mind blank-firing guns are still very dangerous. Other than the obvious, there's also hot brass coming out of the gun. People need to be very safe around guns. Lexan needs to be put up to protect the camera crew (if fired toward camera), people need to be shown the weapon and know how many loads are going to be fired, there's a protocol if the weapon jams, etc. Speaking of jams, if the gun is a semi-auto it will only cycle if you're using full loads. With a revolver, you have the option of using full, half, quarter, primer caps, etc. which can vary by location. Are you in California?

Also, keep in mind that if you don't hire a union armorer or prop guy, the prop houses might not even rent guns to you. They usually require insurance forms before they'll rent to you. And then there are the rental and deposit checks. There will be a 2-week waiting period to get the firearm from a prop house if the prop person doesn't have the proper credentials (FFL or DOJ certification).

We did a test back in film school. We set up a Coke can 20 feet away and then fired a full load at it. It put a hole clear through it. Just like it put a hole in actor John Erik Hexum's brain when he was messing around with "blanks" and fired one into his temple. The only difference between a real bullet and a blank is the projectile. Notice I didn't say the absence of lead. There's still a "wad" that comes out of the muzzle with the same velocity and is dangerous within 30 feet.