And yet, he's done it
on duty pistols.
...
This is one of those things that an agency's head armorer (or gunsmith) can decide to take it upon themselves to approve, with the conditional approval of higher ups, of course.
The former head armorer I initially worked under at my agency built PPC revolvers and made some very nice 1911's and the occasional High Power that included quite a bit of "non-factory" modifications. He was also a machinist before entering LE and a PPC shooter back in the day. He could work on both S&W and Colt revolvers, too. (We issued S&W and Colt Pythons at different times.) He was also the guy who was able to authorize the use of non-factory parts and modifications done to both duty guns and personally-owned guns (carried off-duty). Broad and willing shoulders.
After I'd started attending armorer classes - and he'd spent a lot of time standing beside me and looking over my shoulder, adding to my classroom training

- he eventually approved and authorized me to do some judicious spring replacements and some "smoothing" off the occasional issued guns - selectively, and as approved by him, to his standards, including some personally owned/carried guns.
Obviously, he bore the ultimate responsibility for anything done outside of "factory authorized" parts and work, and he was very careful on allowing his armorers to do such things.
It was pretty standard in armorer classes for armorers to be taught how to recognize unapproved modifications that might be done to agency weapons by individual issued users. Spring clipping was the most common thing to check for someone having done "on their own".
The usual liability concern was that someone might modify a service gun without approval and end up having the modification be the cause of a duty gun not working when desperately. Of course, right? And most especially if it resulted in someone being injured or killed when the gun didn't work as intended. Cop user or a member of the public.
Someone wanting to change to different sights or grips was normally approved, but it still had to be either done by one of the armorers, or by an "approved" outside gunsmith (on a case-by-case basis) but there were more smiths available locally back then.
Then, the growth of custom companies complicated things a little bit, like if someone brought in a personally-owned gun returned from some "custom work" and it didn't pass inspection (or wouldn't reliably function) then it wouldn't be approved for use. If it was a personally-owned gun the
owner was out the cost of having it restored to normal function and could carry some other approved personal gun until it was repaired. As you might imagine, approving such work done to an agency-owned gun might be a little trickier (and cost the issued user more money to restore the agency's property).
Modifications to duty weapons that ended up compromising normal operation (or actually damaging them) could also risk a situation where a gun company tech or smith might end up being called upon to examine it, and then disavow the work done because it didn't conform to factory specs as it was produced and shipped. Think, "Hey, that's
not how we designed it or built it, so it's YOUR problem."
If an injury or death was involved, the liability noose could tighten, and admin/exec folks might start looking for someone to be without a chair when the music stopped.
I remember when some of the older hands at S&W would tell how they used to clip springs to give private owners a "lighter trigger", but it was easier to teach armorers to just stay with factory spec parts and approved repairs. After all, most armorers are
just armorers,
not trained gunsmiths, although there are armorers working for agencies who are also trained gunsmiths. I've met a few of them. I'm NOT one of them.
Another way to get caught by surprise is for someone to come back from some training class at an outside agency (or school) ... and casually mention that an armorer at the other agency had made some modification to their an agency-owned gun, which had coincidentally come back with a functioning problem that hadn't been present before they'd let the other agency armorer "work" on the gun. One time when that happened with one of our plastic-framed pistols, it turned out the other armorer wasn't even trained or familiar with that make/model gun, but had tried to apply their armorer training on one make/model to a different make/model. As a favor, of course.
I was occasionally called and asked to help another agency's armorer with a problem, or to repair a gun owned by another agency who didn't currently have an armorer. I always made sure that my boss not only knew of (received) the request, but had authorized and directed me to perform it for the outside agency as a courtesy ... and that it
was a make/model I was trained and authorized to support and repair. Liability, and taking the steps to reduce needless exposure to unnecessary liability.
I always made sure that I had approval to repair personally-owned guns, too. Most of the time I had the person requesting the repair or modification submit the request above me, and then I'd be directed to perform the authorized work.
The last thing you'd hope any armorer would ever want to do is find themselves in the position of having to explain why some "custom modification" had ended up compromising the reliability and functioning of someone's gun when they desperately needed it to work ... meaning making that explanation to the surviving widow of the user.
Naturally, I used being trained to support and repair some different makes/models of popular firearms as justification to being sent to a growing number of armorer classes and recerts over the years. (The unspoken flip side of
that coin was that I wanted to be able to continue to support and repair my guns once I retired, without having to find some local smith to do simple field repairs.

)
A man's got to know his limitations, right? And if he's smart, to stay within them.
Did I mention that I'm NOT a gunsmith, but just an armorer for some guns?
