Well, 'The guy at the range' is wrong! I know a few things about working tool steels that are unknows to me. No one who makes much of anything wants to say what the item is made of. They have funny ideas about priority over details such as these.
I can just about promise you, that if you heat up a cylinder from any gun with some source of heat that will harden it, and then go drop it in water, you will be missing a part of what ever it was... Not to mention the blueing will be gone, and then even IF you did harden it, it then will be glass hard, and bust to bits under concussion of a charge of powder and by then you will be really having a bad day! It probably won't even be round anymore.
More or less these types of guns are soft, and only some parts are hardend or should be hardened. Cylinders and barrels should not be hardened. Hammer faces, perhaps screw holes, and springs should be hardened and then tempered' drawn depending on what chore they do. The part of the trigger that fit the hammer should be hard too, for a good trigger pull, but I am not meaning glass hard either.
Not many parts of anything in a tool or a gun are at full hard in the first place. Brittle glass hard items tend to crack in use and from being dropped.
If you can file the metal is isn't glass hard. Sheet rock screws are damn hard and yet not glass hard. (I don't advise this test as you will ruin a good file)
A water quench even for W-1 steel doesn't mean you quench in water to get glass hard, and if you do it will probably crack. Incase anyone wants to try that, a horse shoe rasp is w-1.
There is a lot of mumbo jumbo out there in tinkerland, and if you listen to some guy at the range much, I get the feeling it will be hard on the wallet.
Maybe if the guy was a blade maker, and said something you could understand more. Chances are some guy at the range is a paper pusher, and thinks he knows things he PAYS others do do.
I got a lot of junk made, making knives untill I discovered the right guy in the right place to set me straight.
I wasn't happy the day I smiled, oh more like grinned, at my ever so special art knife, and he took that knife, and with his own whittled off the blade like it was balsa wood!
Looking back at things I guess that was pretty fine by me, since my blades sell best at Voo after 'some guy from the range' wants it, but not bad enough, and I take his store bought junk stainless, and whittle it off for him with one of mine..... Mine are pure hell on pot hook of steel too. I will shave of slivers off one side, after I hack up and down the pot hook using different parts of my blades so they both take hits.
Then if you want my blades you pay up, like right now, and if you don't yer a fool... Not much happens to mine after you wipe off the dust and debries...
Of course all my recipes are a secret, one item I use in the method is a very hard to come by Bat's blood!