leverfan,
Oh it is showing up in the field too. If the new short-fat cartridges are more accurate because these rifles are being cranked out on relatively new tooling why are they more accurate than the same new rifles that are chambered in older cartridges(such as the .300 WSM being compared to the .300 Win. Mag. in new rifles of the same manufacture)? Small groups and tight lines to all. Lawdog

New reamers, especially for the initial runs. It's a common phenomenon in the shooting industry, new cartridges are often seen as being especially accurate. New cutters, reamers, sometimes new receiver designs.
There are plenty of long range records shot with the old 300 Winchester Mag, it just takes a good rifle, and consistent loads. The advantage of the short, fat case shape shows up in tiny fractions of an inch in competition rifles. That wins benchrest matches, but it doesn't matter a bit when you're taking a shot over a rolled up coat at a buck with your favorite sporting rifle. Unless, of course, it helps your mental game and improves confidence in the shot. That's important, too.
Even if I was having a long range "beanfield" rifle built, I wouldn't care if it was chambered in the old magnum style or the new short mag style. I've seen how well the old belted mags can shoot, and in a quality rifle, under field conditions, nobody could tell the difference. Even from the bench, unless it's a bench rest rifle with competition grade reloads, I'd have to say the vast majority of folks just can't tell the difference in guns of similar quality. Just my :money: