I just came into a small quantity of vintage ammo marked ".44 S&W R" and ".44 S&W RUS". The case is shorter than standard .44 SPECIAL. Obviously there is a difference, but what is it? Is this ammo safe to shoot in a .44 SPECIAL revolver? Does it have more value as collector ammo or just "shoot em up" ammo? Or is the value in the cases? Most of it is REM-UMC and is in the red and green Kleenbore boxes.

That is .44 S&W Russian, just like the stamp says. It is the cartridge used in the .44 single and double action large frame top breaks. Yes, you can shoot it in a .44 Special. BUT, it is quite collectible. It might even be loaded with black powder. You should sell it and buy .44 Special.
It is usually loaded just a little bit lighter than .44 Special. Brass and bulled diameter are the same. It's like shooting .44 Special in a .44 Magnum.

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Chris
SWCA #2243 SWHF #292

I too have some 44 Russian..some loaded ammo and some fired. Mine is Remington brand and it has balloon head cases. The loaded ammo is loaded with smokeless powder of some sort.

.44 Russian was dropped from U. S. commercial production around 1957, but it still shows up at gun shows occasionally. I wouldn't shoot it just because it is uncommonly seen today and does have a little collector value. As an item of interest, it was the first inside lubricated bullet handgun cartridge made - that was a Russian idea. It is the direct ancestor of the .44 Special and the .44 Magnum.