Here are the SAAMI drawings:
And silly me I still feel like a good .30/06 will satisfy me right down to the ground.
Got me confused? Winchester already makes a .270 Short Magnum.
6.8 mm is the metric designation for .277. What we on this side of the pond know as .270. How much difference can there possibly be? Between their old 270 WSM and their new 6.8 WSM.
Years ago at the old Prescott Sportmans range. I happened to be shooting next to a young guy, who was shooting the then new 30 WSM, (at $30+ a box). He went into chapter and verse, telling me how it was the greatest thing since sliced bread. I didn't say any thing, but thought to myself "what bunkum!" Only advantage the 30 WSM would have over a 06, would be able to be fired from a BA rifle with a shorter receiver.
I just spent a few minutes measuring a new .270 WSM case and comparing to the SAAMI drawing. Diameters are virtually identical. Body length & total case length are 100 thousandths shorter than the "standard" WSM. Maybe to fit in an AR?
The intent is to mimic the 6.5 PRC length which maximizes the seating length for the longer VLD bullets without having any significant impact of the attainable velocities. This is for magazine feeding not single shots.
Quite frankly, with the only difference between the 6.5 PRC and the 6.8 WSM. Is being the .013 greater bullet diameter of the latter. Just don't see the point? How much difference in velocity would there be? firing comparable bullet weights, between them?