Watch the video . They are using expensive thermal imaging night scopes . But at the first shot ( Pow!) the hogs all start too run . What if it was a barely audible ‘ pack ,pack, pack ‘ ? Tell me if large caliber rifle’s report can’t be choked down enough to not to alarm the whole herd ? There would be hogs dropping and the other ones just looking around for the source of the thuds . Possible or not ?
Google 50 caliber air rifle. Sound like it would be about what you are talking about.
We use IR and silencers and they still run, the impact of the bullet hitting meat makes a loud pop and the bullet breaking the sound barrier cracks also.
Suppressors do not reduce the noise enough. They do make a substantial reduction but the shot is still more than loud enough. Also, bullets fired out of long guns, in most cases, are supersonic and noisy. Putting a suppressor on a firearm using subsonic ammo would be the best bet.