Oddly, this silencer was mentioned in two conversations I had, in the span of only a few days. I was prompted to do some research. SF isn't a brand that makes things, especially silencers, for no reason. I can't quite figure out where this can fits in though. They say it's for barrels 10" or less, with the main difference from the RC2 being the larger bore diameter. All other stats are the same, to include weight, which seems to indicate no extreme internal design deviations. The RC2 has been in use on MK18s for years, with no issues that I have read about anywhere, and military and LE don't employ ARs with barrels shorter with any regularity, or at all. Considering sub-10" weapons like the HK G36C and Sig 553 falling from favor, that couldn't be any inspiration for the creation of this can either. Could it be different contemporary 5.56 loads out of the MK18 causing problems, that prompted the creation of a specific silencer for shorter barrels?

Edit: In another internet search, immediately following the creation of this thread, I found a discussion where two different people said the SB2 was designed with the G36C in mind. Interesting, as the G36 in general gets little love nowadays, and any unit using a suppressed G36C would likely be using an AR15 instead, if they're able. In my minimal experience with the G36C, I can see where it would benefit from the larger aperture, in terms of back-pressure reduction, as the system isn't "self-regulating", as some folks say. And perhaps some rounds do have a hard time stabilizing out of that short barrel; I have only shot M193 out of mine, with no apparent issues.

Maybe the 'SOCOM SB2' is simply the result of design criteria developed to meet the requirements of a Military Defense contract/customer, specifically where a low back pressure can for a G36C application was requested.

That's my thought too. Seems like a very niche can to make available commercially. I wonder if they're just seeing how it'll do, or made a certain amount more than the contract requirement, and we'll see the model disappear once they sell them all. Or it'll stay around forever because it's SF, and people will buy it. I reckon it's already been around for a few years, as best I can tell. I don't know when it was initially offered.

as you know I'm a surefire user. I don't have barrels shorter than 10" but I was advised to use an SB2 when shooting frangible ammo of which I shoot a lot even on longer barrels. I am told (but have no way to verify) that the internals are mildly different and of course the bore size as you note.