That's Systema. It's for PTW only.
You may find other M4 barrels with the USGI stepped M4 profile in a similar finish though.
On closer look, that could be a real AR, the stock is not cut the same way Systema does theirs (for the battery).
Age verifier Northern Alberta
Democracy is two wolves and a sheep discussing what's for dinner.
Freedom is the wolves limping away while the sheep reloads.
Never confuse freedom with democracy.