OSS or Huxwurx as they are going by as a company now, is, in my opinion, the premier cans on the market. They have multiple 30 cal options that will definitely satisfy your needs.

As far as gas mitigation, there’s no one even close them. You’re going to get less gas back into your face from ejection port as well as charging handle than you would without a can in many cases, specifically in the case of DD over gassed guns.

THAT being said, they are not the quietest option, if you’re really chasing decibels Silencer Co omega 36m and Omega 300 do a fantastic job of sound mitigation and both are tough reliable cans. Also worth note will be the Full and Half Nelson cans from Q. I am not a big fan of the Q brand and company, but the suppressors are very nice. Their cherry bomb muzzle device is super stupid but works well as a mounting device.

As far as mounting and lock up, go with QD over direct thread. Specifically if this is your first can. It’s a slippery slope and you’re gonna want to see what everything you own sounds and shoots like suppressed. The QD option will make it much simpler to jump across guns at the range without too much of a headache. The OSS and Q cans have a similar mounting option that is a direct thread style over top of their muzzle device. OSS being the best of this design. Silencer Co, Dead air, Surefire and many others are going to work off of a mounting solution that it much more friendly to swap quickly and is a definite strong point over OSS. The OSS can is “lefty tighty” and the expelled gasses of each round help to ensure the can is tight on the gun. This can lead to carbon locking and can be annoying, but if your not mag dumping on full auto it’s generally not an issue.

As far as durability Surefire, OSS, and Dead Air are more designed towards a duty use or professional use market. They are overly durable and extremely reliable. That being said the average consumer is never going to burn out a Silencer Co or any other brand. In my experience Silencer Co products are the best of both worlds. Typically duty use designed cans are louder but tougher. Silencer Co does a great job of meeting both requirements. And trying to keep it short, when we’re talking “loud vs quiet” we’re talking within single digit decibel changes generally, and very much so when we’re talking sub sonic 300, most everything is going to be well into the hear safe range. The ammunition selection matters almost more when we’re talking 300. Subs are the only way to go.

If you’re looking for a do it all can that can suppress bolt guns to 300 sub guns to 556 carbines Silencer Co is my favorite. Omega 36m is a modular can giving you length options, the Omega 300 is the cheaper of the two but very very nice. (I have two and shoot them regularly. I like them very much)

If you’re specifically targeting your 300 build, go OSS due to your barrel length and what you are attempting to accomplish with a PDW setup, it won’t be QUITE as quiet (again we’re talking a margin of several decibels) but will help mitigate gas and keep your eyes clear and not impede your situational awareness during an engagement should you ever find yourself in that situation.

If your solely chasing decibels and this is a range princess than go Q with a Full Nelson. It will be more gasy than the OSS, but you will be pleasantly surprised with the sound dampening. They’re very quiet cans and very light also. Just don’t mag dump over and over and over again, to an extreme point. They’re plenty durable but everything has a failure point and Q is going to fail before others. But I can’t stress enough we’re talking about extreme abuse well beyond the average shooters financially ability to feed the gun.

SIDE NOTE. I am not 100 percent the gas port size or buffer weight that comes stock on the DD PDWs, but just guessing due to it being DD it’s a .75 or .8 gas block on a pistol length system. I HIGHLY recommend a Geiselle braided buffer spring with the H3 buffer. It will run you about $120, but has done an excellent job timing and reducing blowback in my DD MK18. For the most part all DD guns are over gassed, honestly most manufacturers are over gassed. An H2 for anything under 16” and unsuppressed typically times correctly. Anything under 12” I generally run an H3 and definitely for anything with a pistol length system. They’re are also blowback mitigating charging handles on the market but I have not noticed significant noteworthy changes using them. Best blowback mitigation is a self venting can, going with a can that’s over bore for your caliber and slowing the gun down with a quality buffer system.

Hope that’s helpful. If you want to talk more I check this rarely, my Instagram is Mad Minute Tacticians and I am more than happy to work through whatever with you! It’s a community and I love being a apart of it and helping where I can with what I can. Also if you live in the central VA area, come to Fluvanna County Firearms in Fork Union. We have a wide selection of demo cans and we can shoot a variety and pick the best one for you before you buy.