Being a firearms instructor, upon occasion there are a number of firearms which I'll not carry as defensive weapons for a period of time, but which are used just for range training & practice.
That being the case, there are times when those specific guns aren't cleaned after range sessions. Sometimes it's just a couple of sessions, and sometimes it's for several sessions. I've set aside guns and fired them for anywhere from just several hundreds rounds to upwards of a few thousand rounds before cleaning them.
Guns which have been used for this sort of 'abuse' have included any number of my revolvers, 1911's, 3rd gen S&W's, Glocks & my SW99's. I've also participated in abusing T&E guns by shooting them for extended periods without cleaning.
Mostly the guns which have been thus abused have ran just fine as they became dirtier. Being run dirty, however, doesn't mean being run dry. A timely reapplication of lubrication to a dirty gun is a good thing. After all, it's commonly been mentioned that a dirty/lubed gun often runs better than a dirty/dry gun, or even a clean/dry gun, when things start to heat up.
Now, you'll note I just said "mostly" when referring to the observed performance of the guns I used. There have been some occasions when a dirty gun exhibited a feeding/functioning problem which was directly attributable to it's dirty condition. It can happen folks.
I can't count the times over the years when folks came in off the road to qualify and discovered that their improper cleaning practices resulted in guns that failed to properly function as the guns became heated from shooting a couple or more mag loads. Sometimes within the first several shots (really grungy, dry guns which obviously hadn't been cleaned for anywhere from one to several prior sessions ... which is why policies have to be written requiring cleaning of duty weapons before leaving ranges, folks.
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Another thing I'd mention is that as an armorer I've had to resolve more functioning problems caused by improper cleaning practices than I've ever had to resolve caused by actual gun problems.
It's often seemed to be divided between grungy/dry guns and grungy/wet guns, although the 'wet gun' problems often included conditions where firing pins became fouled by an accumulation of gunk seemingly brought about by allowing excessive amounts of solvents, CLP's & lubricants to migrate to the firing pin channels.
I recently has a 3rd gen S&W TSW brought to my attention with a hammer follow problem (hammer wouldn't stay cocked in single action after some shots). The inside of the gun was slathered in a nasty combination of solvent & oil which had congealed within the fire control parts. The sear was not free to move and catch the falling hammer, it seemed. A detail strip, examination and cleaning (meaning the inside of the frame was left clean & dry, with oil only being applied to those spots recommended by the manufacturer) revealed no visible problems with the actual parts. It also immediately restored the gun to normal functioning, confirmed by live-fire in the hands of the user and another instructor. Some discussion with the issued weapon's user was done regarding prudent cleaning & maintenance practices.
This is one of those risk assessment, individual choice & responsibility issues. There are some inherent potential consequences for decisions and actions.
I like to reduce the potential for exposure to unnecessary liability. I like to make sure my carry weapons are in optimal condition for normal functioning according to their design and manufacture.
If a given weapon doesn't run well because it may be dirty and improperly maintained, that's not the fault of the weapon, is it?
Sure, I may prefer a dirty/wet gun over a dirty/dry gun ... but I also prefer a clean/wet gun over either.