One thing I have taken notice of when shooting my R9S and when my son was shooting his, was the total lack of a solution for immediate action drills based on what we have been trained to do.
While my R9S has never malfunctioned, my son's did twice in the first two magazines fired. In both cases it was a failure to feed. The routine trained "immediate action drill," should be ...tap, rack, bang. Doesn't work at all. In fact just trying to get the magazine removed with a partially fed round is an experience. Normally with a magazine that doesn't want to come out, I would just lock the slide back and with my finger try to push the offending round back into the magazine enough until it came out. That doesn't work either because first there is no slide stop or lock and second, the magazine release is not conducive to removing the magazine with a round partially fed. In this case it was almost a two man operation that involved me holding the weapon pointed down range and holding the slide open to remove the pressure, then my son worked the mag release and with his swiss army knife pried slightly on the mag base plate and the mag started out enough that he could pull it the rest of the way. I can see that part of that was caused by a new magazine with a very tight mag spring.
The immediate action drill for a stovepipe might actually work. This is where your support hand moves across the top of the weapon, hitting the offending case and pulling it out of the port as it goes by. However, I have my doubts that this would allow the slide to be retracted enough to continue the feeding process. I will have to try this with the dummy snap cap rounds and a cartridge case to see how well it works.
I'd be interested to hear from others on what they have experienced and any solutions.
