Seems like new generations of drones aim to float around the 50,000+ foot-level anyway, which is well outside of rifle range. It would take guided missiles to hit those kinds of targets.
Adaptive optics and diode laser 10Kw modules would reach out and touch them. That said, RC models aren’t flying based on the exact same aerodynamics effect mix as larger aircraft rely upon. And, the smaller the UAV, the more “attached-vortexes” dominate flight.
Outside of killing the propulsion module or control system, they will continue flying even resembling Swiss cheese.