I got an email from Brownells that they Gemtech GVAC uppers are now available.

I know most of you won’t care, BUT these are extremely exciting because they incorporate Gemtech’s bore evacuator technology. This makes gas much less likely to come back into your face, which is a common issue with suppressed shooting (especially if you are using a higher blowback pressure suppressor). Gemtech’s Integra uppers featured this technology prominently; unfortunately, the reflex-style suppressor made the handguards far too hot to hold in short order. If you are making a rifle that is going to spend most of its time suppressed, this upper seems like a really great idea.