I have been reading the posts regarding the piston operated Stag Model 8 and it seems that everyone is quite satisfied with their rifle. I however have had to return two model 8s because of severe gouging in the upper receiver in the area where the charging handle rides when the bolt is in battery. Neither of the rifles had been modified and both had fired 120~150 rounds of American Eagle Tactical XM193 5.56 x 45mm 55 grain FMJ.
What follows is the scenario for both rifles.
First time out to the range. Less than 70 rounds.
Field stripped the rifle and cleaned it. This included the gas piston. No problems noticed.
Returned to the range a few days later. Another 60 rounds.
Noticed misfires and "delayed" firing. The firing pin detents on the primers for the misfires/delayed firing rounds was ever so slight.
Returned home and cleaned the rifle. Only this time I noticed that there were metal flakes near the ejection port and sever gouging in the upper receiver.
Returned the rifle to Stag. They replaced the upper and returned the rifle to me.
The scenario for the second rifle was the same as for the first only this time the gouging was not as severe. Stag issued a return UPS label and the rifle is in transit.
I am curious if anyone else has experieced a similar issue with their model 8?
Here are some pics. Sorry about the quality, but the area in question is the shiny silver area below the sring to the right of the machined out rounded area. The is about an 1/8 inch deep.