I carried full length variations of the M16 for over 20 years.
Found with basic maintenance they would eat live or blank rounds with equal gusto.
Most feeding problems with blanks was one might not be all the way back in the magizine and would slam and hang up before hitting the ramp into the chamber.
The next would be someone hanging onto the magazine and pulling back while firing. That could cause a jam with either blanks of live rounds.
Powder and charge do make a difference in bullet performance. Firing the same round from the longer barrel M16 and the shorter barrel M4 will develop 2 different muzzle velocities.
The original problems with the M-16 began with powder. The AR-15 was tested using DuPont CR8136 (tube) powder, but Olin Mathieson WC846 powder (cap and ball powder) became the standard for the M-16, even though it increased the cyclic rate and caused excessive fouling. The service also increased the rifling from 1:14 to 1:12 which increased accuracy, but decreased short-range lethality.
The M-16 and M4 both suffer from the same malaise: government contracting. it’s not reasonable to expect the government loggies to keep up with the civilian market, but then again, there wouldn’t be a civilian market without the original military variants...