My personal feeling is that there is no ballistic advantage to being short/fat. For instance, the .300 WSM has the roughly the case capacity of the .300 H&H and it performs like a .300 H&H (duh). Yes, it is a bit nice to be able to have H&H performance with a short action, but I've never seen any particular mechanical advantage to a �-inch shorter bolt throw.
Will the new short/fat cartridges give more velocity with less powder? Nope. Will the short/fats give superior accuracy simply because they are short/fat? I don't think so.
When it comes down to accuracy, the four B's come into play. Accuracy comes from superb Barrels, Bullets, Bedding and Brass.
In my mind (which is admittedly cluttered), case shape means absolutely nothing. Case shape can, however, facilitate handloading and feeding. Longer, slightly tapered cases tend to feed better and minimum-taper cases with sharp shoulders (Ackley) tend to stretch less. Short cases, especially minimum-taper ones, are difficult feeders.
Back to your original question, my feeling is there is no magic in short and fat, other than they are cool and new. And there is a lot of allure in that.
The fact that they ARE new should tell you that the cases are made on new dies and with the most recent technology, indicating that the brass is likely to be first-rate.
We have all watched the PPCs sweep the benchrest matches. My personal feeling is that if .223 (or 6-45) cases were made with the same care that the PPCs are if the same percentage of shooters were shooting them, you'd have a dead heat. My opinion only.
Having said all of the above, I am not a scientist. I just muddle with wildcats and have a lifetime of experience in the field.
Steve
