This year, Hornady introduced two factory loads for the .300 Whisper. One is a subsonic number firing a 208-grain A-MAX bullet at 1,020 fps, while the other is supersonic firing a 110-grain V-MAX bullet at 2,375 fps. The .300 Whisper was developed by J.D. Jones of SSK Industries intended to belch out a heavy bullet with a high ballistic coefficient at subsonic velocities. In a suppressed gun, the Whisper is "silent," hence the name.
But a suppressor isn't a silencer. There are two main elements responsible for the noise we hear as a gunshot--the high pressure gases escaping from the muzzle, and the sonic boom created by a bullet as it passes through the air faster than the speed of sound (1,080 fps at sea level).
Think of the expanding gases like a balloon popping. As the pressurized gas in the balloon escapes the confines of the ballon, it "pops." A suppressor works by moderating the expanding gas.
As for the supersonic crack, anyone who has spent time in the pits at Camp Perry knows you need to wear hearing protection even though the shots are fired from 1,000 yards away. That downrange crack of the bullets is made because the air passing around the bullet slams back together behind the bullet. It's much like how a bullwhip makes a crack, and is something a suppressor cannot moderate. The answer, then, for the shooter who wants a "silent" load is to use subsonic loads.
I'm very glad to see suppressors gradually becoming more accepted and mainstream in America. In many foreign countries, one wouldn't think of hunting without a suppressor. The noise, after all, would disturb the neighbors. Game departments across the U.S. are slowly but surely accepting that suppressors aren't some evil assassin's tool and are allowing them afield.