Bob33 - What is the story with all the new "short mags" that have come out? Is it just the weight issue?
The short magnums are designed to achieve similar or improved ballistics to the regular round but in a shorter, fatter case.
The primary advantage in most instances is that they work in short action rifles. Short action rifles are a bit lighter. In a few instances the short magnum round outperforms the regular round; the 270 is the best example of that.
There are some drawbacks. The magazines typically hold fewer rounds because of the fat cases.
Some will say the short magnums are inherently more accurate because they use a shorter action. Some will say they have less recoil because short fat cases are a bit more efficient (they use less powder to get the same velocity.)
Also, if you do not reload there are fewer factory ammunition offerings in the short magnums.
I place a high value on rifle weight, so I always suggest considering them.