You can shoot all of them without hearing protection. Some are louder. I haven't heard a Tripple X but it's supposed to be the loudest, and most durable. From my observations of cans on ARs, they are not quiet. I'm not saying compared to and MP5SD running sub-sonic ammo or something, I mean compared to a 308 bolt gun. I probably wouldn't shoot any of them a lot without hearing protection. If you want quiet, go with Gem Tech, SWR, SRT. If you want full-auto mag dumps get the Tripple X. I like the flame and noise from full-auto, but I want one for a varmit rifle so I can smack sage rats all day comfortably.