Excellent visual and explanation of the 3 bore and gas key function

[montana]

https://www.youtube.com/watch?v=Uv6a1hs9U5o

[BVickery1974]

I really like this guys channel. He even has a simple homemade lube to make.

[LRRPF52]

I made this diagram over a decade ago, but the actual cutaway live model is great to have.



Bill A. was really big on keeping parts gauged and made or had made his own specific 6.5 Grendel gauge sets, which were part of a standard armorer’s set for everything else on the AR-15 that was common.

He talked a lot about the inner bore dimensions and a correct gas system configuration that often gets overlooked by almost every DIY builder.

If you ever wondered why the Chain of Command told you to clean weapons bone-dry, it’s so the armorer’s could inspect the weapons with their gauges and not have carbon throw off the measurements/GO vs NO-GO gauges.

[Stugotz]