The simple, one step lacquers are all going to fail, eventually, from gun cleaners and lubricants. The good news is they clean right off with lacquer thinner, and you can reapply them. I used Krylon artists spray clear on a Nitro Special, and it has held up pretty well the last few years. It soaks right off if you are so inclined. On my gun, the finish is a bit uneven, but, I just wanted to protect the 80 year old colors, and it has done that. All I can ask, from a rattle can, really. I always strip the gun down to bits when I spray one, and mask off where it shouldn’t be.
Brownell’s at one time sold a baking lacquer, you sprayed it out of a commercial paint sprayer, let it cure, and then bake it in an oven. I did an R10 Darne with the stuff, superb product that is tough as nails, if a bit glossy. Bet if you tried to take it off, the cyanide colors on the R10 would come right along with it. When I have come across a finish that doesn’t seem to want to come off, on metal parts, my last Hail Mary attempt is with regular, Berryman dip type carburetor cleaner. It does not damage case colors if you don’t scrub at it. Stinky, high toxicity stuff, outdoors, wearing a face shield and rubber gauntlets. Your safe yearly exposure level to methylene chloride is actually zero, and you will be getting a good dose with this stuff.
I have used catalyzed automotive clears on many things in the past. Same thing, tough, might be a problem getting it off, actually, but, these are pretty toxic products and processes, and not really for amateurs. Your garden variety Remington guns had a similar finish on the wood back in the 60s-70s that most folks are familiar with, the stuff is tough, and tougher to remove.
Many guys just wipe Tru-Oil wood finish on the metal, let it harden up, and reapply when it is gone. I’ve never done that, but, have seen good reports, here, from guys that have. I’d mostly be afraid of it working into the action and gumming things up, but, you should be able to very lightly coat the outside surfaces, if you are careful.

Good luck.

Best,
Ted

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Detroit smells like Berryman’s. Actually, Berryman’s with wiener dog poo-poo in it.