When I started to pull the upper receiver apart, I found that the crush washer was installed backwards.
The barrel nut was so loose that there was play in the barrel.
The gas tube roll pin was not driven completely through, and the proud end was peened and mushroomed over.
I installed a new gas block and gas tube. The new gas block had a nice snug fit to the barrel journal.
The barrel nut was so loose that there was play in the barrel.
The gas tube roll pin was not driven completely through, and the proud end was peened and mushroomed over.
I installed a new gas block and gas tube. The new gas block had a nice snug fit to the barrel journal.