There may be ammo right now but this one of many of the Short/fats that is going to go the way of the buffalo. It will always be around but it won't set the world on fire and shortly other than Reminginto NOBODY will be chambering it.
The fact that it's ballistically so close to the 280 Remington is the actual problem. Nothing wrong with it but on the other hand nothing to really recomend it. It was designed to work with the short barel with the correct powders so, YES it will work just fine with the 22" barrel.
One or two of Remingtons and Winchester short and super shorts will survive and the rest will soon be gone.
Exactly the same thing is going to happen to the Ruger propritary rounds.
Ross