Charlie's and our friends at Potomac Armory have selected a US manufacturer with exceedingly high standards, ISO 9001 standards, etc. This OEM manufacturer makes receivers for many other brands from top forgings
Quality here is tops. Compare to Colt, LMT, Daniel Defense. These upper receivers are high quality 7075 aluminum forged and hard coat military grade anodized, with milspec hardware. The top is Engraved with T-marks. These are military grade uppers, which means there could be handling marks, and the finish might seem chalky. This will go well with a Colt or FN or LMT lower. These are made for performance, and not for finish, but they look great. Occasionally, we are removing from a completed upper receiver, so some grease might be evident.
Charlie's also offers a similar upper receiver with no T-marks here
Mil-Spec
