With my job I assemble hundreds of rifles using components from the majority of manufacturers on the market, and some are very good with not letting lemons out the door, others are not at good. But anything man made is man made, and everyone slips up from time to time. So before I begin I want to state that the purpose of this is not to bash on a company, but to inspect every single component no matter who made it before assembling.
I was assembling and upper for a customer using a well known and respected bolt carrier group. As I inserted the carrier into the upper I felt some serious resistance which is not normal. I took out the BCG and Charging Handle and inspected the upper at first, and after not seeing anything out of the ordinary I focused on the BCG. I noticed an unusual wear mark on the upper right carrier rail and as I looked closer I noticed that the Gas Key was forced into place on an angle. The respective company has been notified and they are taking care of it.
