I just got my first rifle suppressor. It's a KGM R556 suppressor that was "free" when I purchased an IWI Carmel. Since it's full auto rated, I want to use it on an upper for my M16. It came with one muzzle device that is used to attach the suppressor. So, I can only use it on one upper until I buy another muzzle device. I typically like to shoot a 14.5" M4 upper but can use a shorter upper if the sound suppression is significantly better. All else being equal, is there a noticeable difference in sound suppression between a 14.5" barrel and a 11.5" barrel when the bullet is supersonic?