> It's surprising how little firearms have changed in the past century.

Isn't that a function of constraints in the deployment model, which are fundamentally unchanged? A soldier needs <something> with him to hit enemies and <something else> to reload it - and the simpler the better, to facilitate difficult deployments and keep costs down. I mean, the venerable Kalashnikov is still around, despite its well-known shortcomings...

I guess we would see major developments only if we discovered/engineered materials that can perform the function in a significantly better way.