Need help identifying manufacturing marks

[Orionzsign]

Just bought an ar15 for 550 at a gun show. Love the plumb crazy firearm lower but have no idea about the upper. The only markings on the upper are on the frontsight gas block. The marking are 8 R with a crown symbol. Need help guys can you please tell me who made these marks

 

[Dr.Rob]

That is a forge symbol and might not be exclusive to a single manufacturer.