I've noticed when the bolt slams closed is where the slide action is loudest. Not sure if there's a heat resistant material one could put as a shock/ sound absorber between the chamber and bolt...

I believe there's a carbon-ceramic material used on brake rotors that get red-hot during heavy braking without deforming. I haven't seen the process, but would be interesting to try....

Carbon fiber tubes should be easy if there are carbon fiber barrels out for the ARs. I am really interested in Titanium for the weight and visual when welded/blued....

Simple and visually effective. Thanks for the origonal post and reply...

Interesting video if you haven't seen it yet:

https://youtu.be/7pOXunRYJIw