Not as a complete firearm you can't. A few complete uppers havemade it into civilian hands but are commanding prices in the $5000 range. I believe the lowers are registered as machine gun and thus not able to be owned by civilians. A recent article alludes to amanufcaturer in NH possibly beginning manufacturing these for Hk but again, it's still unknown if this will work so HK will allow them to be in the civilian market. It's not a new concpt anymore and other manufacturrs are using a similar operating design now. many clamor for the 416 but I seriously doubt all those asking for them would actually pay the price they'd command. With it being what it is, I'd say a street price would be up over $2000 easily.
I'm not a black gun person so it's not one I'd clamor for or buy.