You will notice the distinction between the two sets is rather obvious: The first two are straight-wall, with minimal taper and no shoulder. The second set have more taper, but more striking is a pronounced shoulder with the .30-06 being more “bottle-neck” than the 9.3 X 62, which makes the 9.3 more efficient than the .30-06 by a significant amount.
The most efficient cartridges are straight-wall and the second most efficient are those with minimal shoulders. Efficient cartridges are those that produce more kinetic energy per grain of powder than others that have to burn more powder (or produce greater psi) to attain the same kinetic energy.
An article appeared some time ago in a gun magazine showing the .35 Whelen to be the “most” efficient big game cartridge. Now, the .35 Whelen IS an efficient cartridge — more so than its parent cartridge, the .30-06, but it’s NOT the most efficient. In truth, it is far from the most efficient because of that small shoulder. Straight-wall cartridges are still THE most efficient, starting with the diminutive .22 RF.
“EFFICIENT” = “Producing a desired effect, product, etc. with a minimum of effort, expense, or waste; working well” (New World Dictionary of the American Language).
A bottle-neck cartridge may give higher velocity than another with the same powder volume, but it will be at the expense of either higher psi or a lighter bullet, and sometimes a much lighter bullet. For example, a .30-06 150gr deer bullet at 2910 fps/2820 ft-lbs at 60,000 psi will not shoot as flat as a .270 Winchester 130gr at 3030 fps/2650 ft-lbs at 62,000 psi (at 54,000 cup/64,000 psi in the distant past). But notice that the .30-06 is more efficient at less psi while producing more energy. That’s due to several factors, the main one being that the .30-06 is a larger bore while the .270 has the same basic powder space. And that difference is magnified when heavier bullets are used in the .30-06, such as a 180gr, 200gr or even a 220gr.
For the same reasons that the .30-06 is more efficient than the .270 Winchester, so is the .35 Whelen more efficient than the .30-06. As far as energy is concerned, the .30-06 maxes out at around 3300 ft-lbs while the .35 Whelen can approach 4000 ft-lbs! That’s an improvement of 21% from about the same amount of powder! And that’s not to include (yet) things like a larger cross-sectional area of bullet producing a larger wound cavity and significantly more momentum which may produce better penetration, all else equal.
So frankly, the .35 Whelen always makes more sense to me as a one-rifle for all things I hunt than a .30-06! Yet the .35 Whelen is simply a necked-up .30-06 from .308 – cal. to .358-cal.! That makes me ask a question: Why would any knowledgeable handloader choose a .30-06 over a .35 Whelen, if such a choice had to be made? And there are plenty of bullets in .35-caliber to choose from in anything from 180gr to 310gr, made by the same companies that produce .308-caliber bullets!
That’s not to suggest that the .30-06 is inadequate for most things but, rather, that the .35 Whelen is a 21% improvement on the .30-06. Logically, for me at least, that counts for something — and I’m not one who is “hung up” on the idea that I “must have” a .30-06 because it’s most popular or due to nostalgic reasons! Nostalgia, if carried too far, becomes a mental handicap! And I already have enough handicaps. Personally, I think the same thing applies to the .270 Winchester! There are better, more efficient cartridges with more efficient bullets — the .280 Remington being one of them. Why? Because it has just enough larger bore to allow for efficient 160gr and 175gr excellent 7mm bullets! To me, the .270 is a wannabe 7mm. It’s not quite there and never will be. On purpose, however, the .280 Remington (.284-cal.) has been handicapped to 60,000 psi (50,000 cup), and the way it’s loaded by Remington to about 55,000 psi, it will always “appear” to be somewhat inferior to the .270 Win. Any politics in factory ballistics or gun writers thinking? Any nostalgia?
I’ve chosen efficient cartridges for all big game hunting…. they’er ancient, and not because I’m nostalgic. To me, it’s a practical concern. I’m getting about 4400 ft-lbs from a cartridge case that’s only 10% greater in capacity than a .30-06, but making 33% increase in energy over a max loaded .30-06 at approximately the same psi.
Yes, if you load a 22″ .30-06 firing a 180gr at about 2880 fps you’re at about 64,000 psi. And, a few powders will do that. And a new rifle will handle that. That’s what the .300 H&H is supposed to give from factory in a 24″. But folks are loading them to over 3000 fps! Do you think the psi is not approaching 65,000 psi?
Using Hodgdon data for the .458 Winchester Magnum, 75.5 grains of H335 behind a 500gr is making 2163 fps/5194 ft-lbs at the muzzle of a 24″ barrel. Momentum is 154.5. In dividing 5194 by 75.5, we come up with a very efficient cartridge. That’s 68.79 ft-lbs per 1 grain of H335. AA2230 is even better than that, according to the Accurate Manual: 72 grains of 2230 is shown as producing 2159 fps/5175 ft-lbs! But the psi is much less than Hodgdon’s H335 at 53,808 psi vs about 59,350 psi (50,300 cup). 2230 is therefore making 71.875 ft-lbs per 1 grain of powder, and at less psi! It would seem to me that both of these powders are capable of producing at least 2200 fps/5373 ft-lbs from a 24″ at less than MAP (62,500 psi). That’s EFFICIENCY!
My Ruger No.1 in .45-70 LT (long-throat) is even more efficient as it’s ballistics are from a 22″ barrel. It is making 2210 fps/5422 ft-lbs from 75.5 grains of H335, plus the 500gr. But the psi is obviously somewhat higher at about 64,500 psi.
If we compare those numbers with a cartridge case that holds about 12% more powder than a .458, but in a smaller caliber, we will verify that a straight-wall case is obviously more efficient when psi is the same, or similar.
In this example we’ll evaluate one of the new kids on the block — the .375 Ruger: In turning to the Barnes Manual, Number 4, pg.349, the highest MV from their 300gr TSX is 2649 fps/4674 ft-lbs from 78.5 grains of powder. That translates to 59.54 ft-lbs per each grain of WW 760 from a 24″ barrel. But the .375 Ruger doesn’t come from the Ruger factory in 24″ — it’s either 20″ or 23″. Then, of course, momentum is far less, plus the bullet being only 67% in cross-section area as the .458″ caliber. Yes, it will shoot “flatter”, but not hit as hard or make as large a permanent wound cavity.
The advantages of the .375 Ruger would be less recoil and a flatter trajectory, while being less efficient. Does efficiency matter? Well, it does if that is the subject, but not if results are the prime objective. And usually they are! If results at less recoil is the topic, then the .375 Ruger wins! If game down on-the-spot is the main thing, no matter rifle weight or recoil, then you choose your medicine!
But, our topic is: “Efficient Cartridges”. So we continue…
In comparing (again) the .35 Whelen with it’s parent, the .30-06, we objectively see these factors which may, or should, determine our opinions of one versus the other in decision making or any debate:
And, of course, these ballistic comparisons can only be made on the basis of handloads as factory loads for the .35 Whelen are practically non-existent. Yes, Remington makes a couple, but they are a very poor representative of its actual potential. So, handloads only for each based on Nosler’s Manual No.6:
180gr (Partition, Solid Base or AccuBond)
Highest MV: 2872 fps/3296 ft-lbs
61 grains of RL-22
Efficiency = 54 ft-lbs per grain
225gr (Partition or Accubond)
Highest MV: 2805 fps/3930 ft-lbs
58 grains IMR4064
Efficiency = 67.76 ft-lbs per grain
As “they” say:YMMV.
But my experience was with two 22″ .35 Whelens, and I’d choose the 250gr Partition at 2600 fps if in a bolt gun. Finn Aagaard’s load in a 22″ was 59.5 grains of RL-15 behind the 250 NP at 2600 fps.
(This NEF single-shot was one of my .35 Whelens)
But, nonetheless, the original point was that powder capacity the same (or nearly so), a larger caliber will ALWAYS be more efficient in energy and momentum than anything smaller in caliber.
Let’s consider one more example, that is somewhat more extreme than those previously given: The .223 Remington vs. the .44 Remington Magnum. They have approximately the same case capacity when bullets are seated.
Both are popular cartridges; the one for small game and varments, the other for self defence and bigger game up to about 400 lbs. One is for varments at about 250 to 300 yards, the other for big game to a max of about 125 yards. But they burn about equal amounts of gun powder, a somewhat faster type for the .44 Mag. One produces about 1200 ft-lbs at the muzzle, the other close to 2000 ft-lbs. One has a momentum of about 24, the other a momentum of 73. They each have a purpose, but the “little” .223 can’t compare with the .44 mag in efficiency! You can shoot “big” varments with either, but only the .44 Rem Mag is appropriate for a 350 lb bear inside 100 yards! And, by the way, the “little” .44 Rem Mag is more efficient than both the .45-70 and the .458 Winchester. It is making about 84 ft-lbs per grain of powder, whereas the .223 is about 57 ft-lbs per grain.
More to come, next time… (Other factors involved in efficiency, only hinted at this time.)