Limited to six shots. FBI data shows that something like 20% of rounds fired during an engagement make it to the target. I own a couple Glocks and their tolerances are so loose that I have literally never had a failure to fire, or more importantly, a failure to eject or cycle. 17 rounds. Have you ever attempted to use a speedloader on a revolver? I am at 2-3 inch groups at 25Y with Federal FMJ. Modern striker-fire handguns are reliable. Yes, revolvers had an obvious edge in reliability, but 1/3 the capacity.
I fired 700 rounds of General Dynamics SS-109 last weekend from a KAC SR-15 Car MOD2 without one failure. All mags were PMAG Gen two and three. Amazing quality DI gun. I will probably pick one up this week from a dealer on Gunbroker.