Several years ago I helped organize, design, and run some "practical" matches at my local club. These were non-IPSC affiliated but we used IPSC rules. We tried some interesting things like revolver-only matches and "Any Gun" matches.
Our first revolver match was very eye-opening. Keep in mind this isn't casual range shooting, this is engaging multiple targets from multiple positions with reloading and the timer going. Maybe unrealistic for most civilian firearms usage, but the artificial stress created must have influence most of the malfunctions we saw:
-.38 revolver cylinder won't close with a .357 cartridge in one chamber
-cylinder not shut completely
-not releasing the trigger completely between shots
-Badly sized cartridge in full moon clip prevents entire full moon from chambering
-loading all cartridges backwards in a full moon clip (cylinder tends to bind) (Yes, some full moon clips have a front and back!)
-Bad timing. Wheelgun goes BANG! BANG! click BANG! click and the shooter tries to go "around the clock" hoping the cartridge goes off again the next time around. By the way this is a great time to find out if you're jerking on the trigger.
-Screw backs out of S+W frame so on reload the cylinder and crane go PLOP on the ground. Saw this happen twice in one day to 2 different 625s.
-Old leather holster: On draw, sight picture messed up from the brown fuzz on the front sight!!
-Squib load: BANG BANG pop BANGGG and then later it's "How did my barrel get bulged??"
-Empty case hangs up on grip panel preventing speed loader from chambering.
-One cartridge hangs up in speedloader so you only loaded 5, not 6. Where's the "hole?" We'll find out in the next 6 trigger pulls.
-Shooter loses count. I dunno how you lose count from 1 to 6 but this guy couldn't figure out why he ran dry until I pointed out he was reloading at strange moments and dumping live rounds on the ground.
-Shooter uses speedloader to reload. That's good. Shooter uses wadcutters. That's OK. Shooter uses wadcutters in speedloader at a night match: BAD MOVE! On the reload I could hear all 6 rounds clatter to the table on the stage in question. Ever try to line up 6 wadcutters in a speedloader at night??
OK, note that most all of these malfs can be avoided by good shooter/firearm relations and management. Good firearm manipulation and practice/training and someone can be a very good and reliable shooter with a wheelgun.
Another note: the rash of wheelgun malfs we saw were with people who were no strangers to action pistol competition. I think we were going into the revolver match from a complete cold start, though.
To me, the key is NOT to think, "HA! Now I will never have malfunctions because I have a revolver!" A good shooter will know his equipment.
A more positive story: One of our later revolver matches I shot with my 5 shot SP-101. To my surprise I came out 5th out of 12 shooters even though the match was designed for 6 shooters.
Hope I helped.
Edmund