Longevity, Accuracy Tips for the AR15

[customcutter]

I was looking for a shaft to turn down, and found one. It was a shaft from one of the deck bearing assemblies on my commercial mowers. It was .9965 on both ends with a .125 shoulder for total diameter of 1.25 and 5" from the shoulder to the end. Deburred it and slid it in. Rotated the shaft while rotating the upper with a strong light in the background. Everything is square on my CMT upper, so I'm good to go.:-)