There's a few reasons why the rate of fire could be lower on video - depending on the spring strength of the buffer tube and the spring inside the bump stock, the weight of the bolt, and the loading of the bullets he used would affect this.
I can't really tell anything about the guns used in the shooting based on the sound though - it's comparing sounds recorded far closer than the gunshots in in Las Vegas shooting footage, so it's not like we can compare the sound of the different calibers too much (M240 uses the larger 7.62 cartridge whereas Paddock's bump stocks were on 5.56 caliber ARs, none of the 7.62 cal rifles he had with him had bump stocks) , though you can definitely tell that the rate of fire varies in the LV footage in a way the M240 doesn't.
From my non-gunsmith brain I would also imagine that gas tube length would also have a large bearing on the firerate, but that's probably mostly pedantic.
I don't know a whole lot about the whole shooting, and I'm sure it has been analyzed to death, but if one really wanted to rule out a magazine fed gun like an AR with a bumpstock i feel like the place to start would be counting the amount of shots heard in between larger pauses
There's a few reasons why the rate of fire could be lower on video - depending on the spring strength of the buffer tube and the spring inside the bump stock, the weight of the bolt, and the loading of the bullets he used would affect this.
I can't really tell anything about the guns used in the shooting based on the sound though - it's comparing sounds recorded far closer than the gunshots in in Las Vegas shooting footage, so it's not like we can compare the sound of the different calibers too much (M240 uses the larger 7.62 cartridge whereas Paddock's bump stocks were on 5.56 caliber ARs, none of the 7.62 cal rifles he had with him had bump stocks) , though you can definitely tell that the rate of fire varies in the LV footage in a way the M240 doesn't.
From my non-gunsmith brain I would also imagine that gas tube length would also have a large bearing on the firerate, but that's probably mostly pedantic. I don't know a whole lot about the whole shooting, and I'm sure it has been analyzed to death, but if one really wanted to rule out a magazine fed gun like an AR with a bumpstock i feel like the place to start would be counting the amount of shots heard in between larger pauses
Someone claimed there were over 200 shots fired without a pause at one point, but I haven't verified that by watching the video for myself.