As you say, I have had and sold alot of guns in my time.
Now I can only speak for a few.
I know a few are still running, and a few have died and been split.
The the one I'm most proud of, was last year at NAF. Saw a TM famas, chatted to the guy, turns out it was my old one.
Now I bought this famas new around 1997-98.
And it's still going!!!! Damn things are indestructible.
The one that broke my heart, was my TM M14 EBR.
This had the full G&P EBR kit, correct king arms Silencer, G&P knights mounts. Real harris bipod. All G&P mid cap mags with 7.62 magpuls. The works.
A year later, saw it for sale on an old forum that disappeared years ago (UKAZ, if any one remembers that one).
Turns out he didn't like the ebr kit, found it too heavy. So stripped and sold it all, and turned it back to the basic M14 socom.
Wasn't long after, that was then being sold for spares as had cracked the body and some how blown the gearbox. But didn't want to repair it.
And that's one of about 5 guns I ever regretted selling.