Can I use long rifle ammo in a Winchester MOD 1904 that calls for short long or extra long?

Answer 1

I looked at the ballistics of both cartridges and I'm sure the barrel and bolt will take the extra pressure.

But there are a couple of additional issues.

First be sure the barrel is clean and bright. Run a few shorts thru it first to be sure it functions properly.
Look down the barrel after each shot to be sure a bullet isn't stuck in the barrel.

Try chambering a 22 long and then extract the round with out firing it.
You're doing this to check that there's enough "throw" to the bolt for the extra length of the cartridge.
Does the bullet extract easily? If it doesn't this is a no-go.
The shell expands when it's fired and if the gun has trouble extracting an unfired cartridge, you'll never eject a spent shell.

Look at the bullet itself, did the nose get distorted during chambering?
(This will seriously effect the accuracy of the gun.)
Look at the sides of the bullet. Do they seem to be scraped up other then small cuts from the riffiling?
My guess would be that the chambers throat was shot out to the point where this wasn't an issue but if you find that it's shearing off metal from the bullet, this is a no-go.

Do the cuts from the rifiling extend down onto the shell casing?
If so, you're probably going to have trouble getting the gun to eject the spent shell.

Be sure and check down the barrel after each of your first few shots.
A bullet stuck in the barrel could cause the gun to explode.