A bit long, but if you want feedback on suppressors and the RFB, here it is.
I'm not one to push one brand over another, for some of the same reasons I don't make investment recommendations. Everyone has their own opinions. There are well over a hundred brands readily available out there, and you can even make your own suppressor. Whichever way you go, the admission price is a $200 tax stamp, just to start. The 30 cal cans I own and my personal experience are listed at the end of this post.
Some of the big names, in no particular order, are Thunderbeast, Gemtec, SilencerCo, Yankee Hill, AAC, and Surefire, just to name a few. Griffin and Rugged are a bit newer, but have some very innovative designs. Apologies, if I left out someone's favorite brand. All of the above appear to make good products and have good reputations. The technology and manufacturing processes are also changing rapidly, and everything is an apples and oranges comparison.
I will make one company recommendation, solely because they are a good resource for research. I have used them, but have no direct affiliation. If you have done any online research or silencer shopping at all, you are already aware of them. I'm not a big fan of their website design, but they are a wealth of information and have a wide variety of products, pictures, descriptions, and reviews in one place (just understand most of the reviews are marketing pitches):
SilencerShop.com -- They seem to have cornered the market on making it easy to buy suppressors online, including hand holding for completing the ATF forms and getting a trust, if you go that route.
For the RFB, I do recommend you go with a suppressor that advertises reduced back-pressure for semi-automatics, and if you plan on doing mag dumps, get one that is full auto rated. Better yet, get one that is magnum rated. Full auto may only be for 5.65X45 or 300 Blackout.
Super light weight may be convenient, but not necessarily durable, or good at dissipating heat and reducing noise. Direct thread designs are simple and convenient, but those that mount over a brake or flash hider can be removed and re-attached quicker for cleaning the rifle, and save wear and tear on the barrel threads. That said, almost all manufacturers conveniently leave out the weight of the required brake or muzzle mounting device when bragging about the weight of their product, and almost any noise reduction or other stated performance characteristics are usually on a long barrel bolt gun (not a semi-auto). I'm not a fan of muzzle brakes by themselves, because they increase noise along and behind the firing line. However, mated with a suppressor, they can make a suppressor's inherent recoil reduction even more effective, aid in noise reduction, increase life of the suppressor, and create a more pleasant shooting experience. Just note, they add another 3 to 5 ounces over the advertised weight of the can.
I shoot both my RFBs almost exclusively suppressed.
I have a Shark suppressor on the carbine. It is direct thread, and reasonably light weight. I would rate it at above average back pressure and decent suppression. It works very well on the carbine once I upgraded the gas system to a Gen 2, to be able to use a suppressor piston. Everyone at the Phideaux Shoot last year seemed to really like it. Shark is a low volume manufacturing company, and I'm not 100% sure they are still in business, but don't let me start rumors. There do appear to be more cost effective options available today.
I also have a Wilson Combat suppressor on the hunter. The Wilson is shorter, but larger diameter (than the Shark), in theory for larger volume to reduce back pressure, which it does a fair amount. It is lighter than the Shark, but the added muzzle brake makes it overall heavier. It does not suppress as well as the Shark, but still useful. I think Wilson has discontinued making suppressors, but there again, don't let me start rumors.
I also have a Griffin Armament suppressor on order, but no experience with it as of yet.
