Anything that shoots above the speed of sound (1,126 fps) is going to make a sound as it breaks the sound barrier. So to answer your question, no a larger caliber can't be truly "silenced" unless you load your own subsonic rounds, which have a greatly reduced velocity and are therefore less effective and more prone to "tumble". However, its a WHOLE lot quieter with a suppressor. You can target shoot all day and not need ear plugs. My best friend as a .338 lapua with a gemtech suppressor, and its one of the top 5 coolest things I've ever played with.