What happened within in parameters of InRange’s mud test?
As Ian and Karl take the AUG apart you can see a couple things. The first is that the barrel, gas piston system, and trigger group are all pretty clean. Mud didn’t ingress into any of those parts. But where it did ingress was the charging handle operation rod channel and enough onto the surfaces of the bolt carrier that weapon locked down.
Again the likelihood that you, while carrying a rifle like the AUG, take a dive into mud like that is… well as likely or unlikely as conditions you are in allow. But it shows the potential weak point and environmental conditions that can take advantage of that weak point, so a user must be aware of them
The “autopsy” also illustrates the likelihood of getting the rifle back into working condition on the fly. Unfortunately, in the case of the AUG, it is unlikely with that much ingress slowing down and gumming up working parts. But that illustrates what a user must do, that under certain conditions maintenance must be performed. A deep clean and lubrication will bring the rifle back into service. A parts survey might be necessary to assure function, similar to if solid debris got into an open AR action and around the gas tube, gas key, or into the chamber.
Rifles have limits. Knowing the limits and fixes for any particular platform are a crucial part of choosing to run it. AK’s, AR’s, SCAR’s, AUG’s, it doesn’t matter. Learn it, objectively, and run it.