Personally, I don't think the gauge of the gun or the length of it's shell has much bearing at all on the "Anti-Hunters". I would suppose if one wanted to "Legally" restrict noise this would be best accomplished by limiting the velocity of all loads to less than the speed of sound to eliminate the Sonic Crack. This would of course impose a limit of about 1100 FPS. I would not support that restriction myself, though I seldom load above 1200 fps.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra