Old Versus New Cartridges: Which Rifle Rounds Are Better?

[Johnny Yuma]

NOT a pistolero, do not like them (as some can tell).
We each have one, and two black powder ones for fun.
I carry an aught six, the women carry ARs in 300 BO.
The 22 rimfire has been a safe queen since the grand kids are in their 30s.

 

[Talyn]

More efficient??? So, my 6.5 Swede or 7mm Mag is less efficient?? Is it less efficient, even if the case is 1/4 longer, or a bit older? Fie on you…you probably believe .308 is better than the30-06…heathens everywhere…we need a witch hunt.

I have 6.5 Swede's, 257 Rs, .308's and 30/06s, and very familiar with the logic that P.O. Ackley came up with with his designs.

No heathen here.

But, I do favor the "more efficient" newer designs. Shorter, fatter case body & sharper shoulder-angle = a more efficient powder burn.

Case in point: the .260 Rem & 6.5CM have comparable performance but the 6.5CM can use longer/heavier more efficiently since they don't intrude into the case body as much as the 260 RM thus have higher performance in those instances. And the steeper shoulder-angle can result in lower case-neck stretching.

Plus the newer case designs can often fit into a shorter action -length whereas a 6.5 Swede & .257 R, being intermediate-length cases have to be either seated deeper (shorter than their most "efficient" OAL) to fit into the typical short-action length, have their own intermediate length action or fir into a long-length which is a bit over kill.