I bought mine through a local class III dealer. There are numerious companies that manufacture suppressors. The first thing is to make sure that you live in a state that will allow you to have one, and live in a juristiction that the cheif law enforcement officer will sign your paperwork. I did a lot of research on mine before I bought, and I went with the Advanced Armament M4-2000. It is a quick detach flash suppressor, that uses a modified A2 bird cage flash suppressor to mount to. It being a .223 suppressor, it can be used on a .22 long rifle, .22 mag, as well as most of the .22 caliber rifles. In SC, you cannot use a centerfire at night, so it is on the .22 mag to reduce the muzzle flash, what little there is. I use it on my AR when hunting during the day. I got it mainly because a lot of the people you ask for permission to hunt on their land, don't care to hear gun fire. It makes my AR sound about like a .22 rifle firing shorts. It is even quieter with Engel Ballistic Research's 63 grain subsonics; all you hear then is the click of the firing group and the bullet impacting down range. Some of the suppressor companies that I recommend are Advanced Armament, Ops inc, Gemtech, SWR. I have heard suppressors from all of these companies and they are all well built, quite cans. One thing to understand about a rifle can is that they are not like what you see in the movies. The most accurate movie example of a can is in Tears of the Sun, when the seal team comes to the outskirts of that village and the seal sniper does some shooting out of a tree. If you want super quite, then you will want a 9mm or .22 lr can. If I am 100 ft away from you and shoot my AR, you will hear something, but it will not at all sound like a gunshot, and most of the noise you hear will be the bullet impacting. I have found that it is great for getting that second animal to come in, because they are not as spooked. There are a lot of class III dealers on AR15.com, and they have a suppressor forum there as well. Another great source of info is on
www.silencertests.com
I would recommend a QD can like the AAC M4-2000, simply because it will not unthread itself when you are shooting. Cans get real hot after only a few shots and the last thing you want to fool with is having to tighten a regular threaded can to the barrel after shooting a few rounds. Also, I would not recommend you use a thin barreled rifle as you platform. Most cans weight in excess of 18 oz, and that will cause a point of impact change in any rifle when you fire with the can on vs. off. My can sits back over the barrel by about 1.5 inches, and extends the barrel lenght by 5.5 inches. You will also get about 50 fps gain in velocity, due to a thing called free bore boost, where the gases are still expanding behind the bullet, but the bullet isn't actually contacting anything. It will also tighten up your groups a good bit. It acts as the most perfect muzzle crown you can get, thats why most rifles that get a suppressor, usually gain a little in the accuracy department. Hope this info helps.