I have extensive experience with those things, and maintained a hate-hate relationship with them during the period I was forced to use them. I have grown to not like DA type handguns in general, while giving what I considered the better guns that share this system of operation their due respect (legacy Sigs like the 226/228 and HK USP variants). I don't like DA either as a shooter or instructor, because I like a consistent trigger for every shot- whether it is the first round out of the holster or the subsequent rounds that will follow in the engagement. They require additional movements to decock after the engagement to re-holster, and the mastery of 2 seperate triggers on the same gun. This is extraneous and potentially dangerous if you forget to de-cock prior to holstering due to stress (like at the end of a gunfight for example).
The M9/92 comes with many of what I consider design flaws. I have repaired many broken locking blocks, and broken a few myself. Despite several redesigns of the part and replacement of the standard slide with the heavier 96 model brigadier slide (but only in SOF units), this problem never stopped. Also, the brigadier slide is shaped slightly different from the standard slide- this means many M9/92 kydex holsters won't work with the brigadier slide.
The only clear advantage of the WW2 P38 style locking block is that it resulted in the pistol having a very soft recoil- but the downside is that limp-wristing the pistol (a common problem for less experienced users and those with smaller hands or less strength) would often result in malfunctions at higher rates than other pistol designs- despite the use of 124 grain "spicy" NATO ammunition. I never saw this until I was tasked with training some support soldiers (many of whom were females-who represent about 19% of the army and 10% of the marines). Unless the user has one of the much newer models, they do not have a light rail, making mounting a light problematic, with varying degrees of success in designs to mount lights (this applies to every M9 in the US army and most others in use everywhere).
Aftermarket grips (esp. rubber ones) are a no-no on this gun- heat or cold can make them flex, which will make them contact the trigger bar, and possibly disconnect the spring inside- making it a paperweight. The only reliable option is to stick bicycle inner tube over stock grips, or stiple a (spare) set of standard grips with something like a soldering iron.
Loss of 1 (or more) grip screw washers will likely result in the magazine being stuck inside the gun. I had to crazy glue these washers into the grips to prevent guys from losing them during deep cleanings- such as when they were packed with the moon dust that gets in everything in afg/iraq and similar environments- and the M9/92 will seriously choke on any significant buildup of foreign matter inside. And crazy glue should never need to be used on a gun, period.
Another frequent issue is the ambi safety/decock levers frequently breaking off the right side of the gun during normal use, right in line with the hole for the roll pin that holds the 2 sides together. Additionally, the safety/decock is in the wrong place (on the slide- if it was frame mounted like a 1911, it would be much easier to access, esp. for users with smaller hands and shorter fingers (like females, typically). The location of the safety/decock often results in it being accidentally activated when clearing a malfunction (which happens fairly often with these guns). When this happens, the shooter will have what we called a dead man's gun mid-engagement.
Slides have been known to fail, with the only consolation being that eventually a mod was made to prevent that slide from exiting the gun and doming the user. Not getting hit in the face with a slide is good, but not having the gun fail is even better.
The internal springs quality also leave a lot to be desired- if these guns are exposed to salt, or just due to age expect them to fail, making your pistol a paperweight again. At least Sig put improved corrosion resistant springs in their pistols. I will say that the user-configurable mag release for lefties was a nice touch- the southpaws seemed to like that feature (11% of the population).
So, those are the reasons that the M9/92 is my least liked service pistol of all time, and I have used more than a few different service pistols. These are actual observations of the pistols being used, and not antecdotes I am parrotting that I read somewhere on some gun forum. All of these issues are annoying in training and very concerning in real world use- much more so than any caliber debate or bullet design conversation. After all, none of that matters if the pistol can't fire for whatever reason. At the very least, it is something else for the user to be concerned about, and does nothing to help a M9 user's confidence in his/her issued pistol- as if military members and LE need something else to worry about.
So, for the M9 fans who love their pistols either due to nostalgia, a love affair with Italian engineering, or aome other reason, I hope you enjoy them and shoot them well, and I hope they never let you down. I was let down numerous times by them and I won't be giving them another chance, just like MRE's, poorly designed boots, and other things I was issued that just plain suck- especially now that I am not forced to use one, and can opt for any handgun I want or even no handgun at all if I choose.
