S&W .22 mag

NO!

Don't shoot 22LR, 22Long, or 22 Short out of a .22 Magnum chamber!

The case will split and could cause damage to you and the gun.

The .22 LR, L, S use a heeled bullet and the case is smaller in diameter than the .22 Magnum

NO!!! The .22Mag and .22LR are two different rounds and do not interchange. The Magnum case is bigger around than the Long Rifle so if you fire the LR in the Mag case you take the chance of splitting the case and getting a face full of high pressure gas.

Can it be done? Yes. Should it be done? No.

The Model 48 .22 Magnum K22 Masterpiece Magnum Rimfire was sometimes sold with a spare fitted cylinder in .22 long rifle. You could call S&W and see if they are still able to fit the spare cylinder, otherwise stick to .22 magnums. As mentioned above the cases are different diameters. .241 for the magnum, with a .224 diameter bullet, vs .225 & .223 for the long rifle.
I wouldn't expect any real damage to the gun, but the chance of split cases and hot gas escaping and potentially damaging your eyes means it's not worth it.

You CAN shoot .22 Winchester Rimfire cartridges from the gun, provided that you can find some.
The same cylinder wall erosion-leading to chamber sticking issues that occurs when shooting a steady diet of .22 Short cartridges in a .22 long rifle chamber applies here as well.

Onmilo said:

You CAN shoot .22 Winchester Rimfire cartridges from the gun, provided that you can find some.
The same cylinder wall erosion-leading to chamber sticking issues that occurs when shooting a steady diet of .22 Short cartridges in a .22 long rifle chamber applies here as well.

Click to expand...

a small, but very important clarification
"22 Winchester Rimfire cartridges"... he means 22 WRF.. and they will be plainly marked "WRF"
which is not 22 short, not 22 long, not 22 LR
the WRF rimfire cartridge preceeded the 22 WMR rimfire in history, and is essentially a slightly shorter lower powered than 22 WMR (22 magnum)

I shoot 'em quite a lot in my k-48, cheaper than WMR and ok for plinking (though prone to frequent misfires, it ain't premo class ammo).. you could shoot WRF in a 22 WMR bolt action (but not WMR semi-auto, be it rifle or autoloading WMR pistol) if you wanted to, but I would not

but like everybody said, do NOT shoot regular 22 rimfire stuff in a 22 WMR, not unless it's a convertible revolver that you have both the factory fitted cylinders for

PS
a k-17 makes a dandy companion for a k-48