Early GP100 revolvers had what would be called “grunge grooves” under the extractor, to accommodate unburned powder debris that might collect there, during an extended shooting session. That, plus the durability of the GP100, I reckon, that makes them true fightin’ sixguns. I bought my first GP100 during this time, and later bought a pre-owned GP100 made during that time.
These is at least gunsmith who does a “powder eater” mod, which I believe is a similar concept. (I cannot recall his name.)
The durability factor includes coil springs, which are less likely to break, than leaf springs. I experienced a broken leaf-type main spring in a duty revolver, which is largely why I established the religion of Carry Thy Second Gun. Of course, the fastest “speedloader” is a second gun, wrapped around those five or six cartridges.
Personally, I find my DA revolvers to be nicely ambidextrous, so, two revolvers can be holstered in a way that allows each hand to have a weapon positioned for expedient access. This second holster, therefore, is a factor in “combat” applicability.
Sometimes, my aging right thumb/hand/wrist do not do exactly what my brain tells them to do. I started getting limp-wrist/limp-grip malfunctions, just before age fifty, with some autos. Revolving pistols do not care whether my grip is firm, or not, or whether my wrist remains firmly aligned, or not. Switching to lefty primary, which would not adversely affect accuracy, as I am a natural lefty-hander*, encounters the challenge of my right hand’s numb thumb being less than obedient when I want it to run a slide, while shooting lefty. So, the age/infirmity factor can favor the fightin’ revolving pistol.
*Left-handed, but right-armed; I write lefty, and throw righty. Carry position was irrelevant until I signed-up for LE work, due to the Texas weapon law, at that time, so I started the academy without having established a primary carry side. I was a blank slate, for learning long-stroke DA, and found it worked with either hand. Drawing from the then-mandated, low-slung duty rig was not unlike an underhanded toss, and I knew my right hip would be more-accessible while patrolling alone, in a vehicle. So, I established right hip carry. A bonus: If ambushed, while eating, and if I am hungry enough, I can keep eating, during the ensuing gun battle.