Re: Long or Short?
If you try to run a cartridge that's normally long action (e.g. 30-06, 270) in a short action, you will have to single feed because they won't fit in the magazine and won't eject cleanly.
Like the above post states, you can technically run a short action cartridge (e.g. 308, 223) in a long action. Also as pointed out, ther are times when that makes sense.
A short action weighs a little less and is generally stiffer because it's the same diameter/thickness, only shorter. So, that often comes into play depending on your requirements.
There are some mfgs that do sort of have in-betweeners. But, I can't list them accurately so I won't try.
In any case, it's mostly not meaningful to cross compare since a Rem 700 bolt short or long win't fit a Winchester action anyways.