Or you can create, from scratch, purpose built guns with the same spec, but are made of materials(like aluminum) that the holder will know is fake from the moment they pick it up. For larger pieces, you could include a co2 mechanism to recreate recoil and include an LED to light up with a trigger pull for sfx people to use as a reference. Pretty sure some of these things already exist.
And quite frankly, the audience doesn’t deserve a perfect recreation if it means putting people in harms way. There’s a thing call Suspension of Disbelief that seems to be in short supply these days. Never bring the CinemaSins guy to a traditional Japanese theater. The Kuroko stagehands would give him an hearth attack.