Efficient RIFLE Cartridges

Efficient: “producing a desired effect with a minimum of effort, expense or waste”. (New World Dictionary of The American Language – Second College Edition).

I’ve always liked and preferred efficient rifle cartridges, and the best of them are straight-wall cases without the typical “bottle neck”. The second best are those with a minimal bottle neck on a straight-wall cartridge. Simply stated: You get the best bang for your buck!

As evidence, consider the lowly .22 Short and Long Rifles. And on the .22-cal end of matters, the .22 WMR. As far as cartridges go for large and dangerous game is concerned, we need not look beyond the .458 Winchester Magnum when handloaded by savvy advanced laymen, they have come up with +6000 ft-lbs of kinetic smash! From a miserly 78 grains of one of the best propellants, I’ve reached 2590 fps from a Barnes 400gr X-Bullet = 5959 ft-lbs! Let’s see now, that works out to 76.4 ft-lbs per grain of a suitable rifle powder. . . . Still not as good as a .22 LR firing a 40gr at 1280 fps – Efficiency rating: 97 ft-lbs per grain!

The .458 Winchester Magnum is very efficient in bullet weights ranging from 250grs to 600grs. This is far from a complete lineup, but they range from left to right: a 600gr Barnes Original to a 300gr Hornady HP. There are a couple of Barnes’ mono X-bullets, cup-n-cores with varying jacket thicknesses, a bronze-jacket “solid” and a couple of cast bullets. Only six of those are still manufactured today. But many new monos are in production as well as bonded versions:

On the left are Federal 400gr TBBC bonded bullets in .458 Win. On the right are handloads of 300gr TSXs using once fired Federal cases. They are mono bullets with hollow cavities. The Federal factory are making 2280 fps (advertised at 2250 fps), and the 300gr TSX’s are leaving at ~2750 fps.

One of the most efficient “mediums” is the .35 Whelen that delivers about 63 ft-lbs per grain of CFE-223. How does all that compare with “extreme” bottleneck magnums? One of my long-term favorites among those is the .300 Win Mag: It’s efficiency rating is about 50 ft-lbs per grain of an appropriate propellant for a 180 – 200gr.

Modern shooters who rave over the .260 Rem and 7-08 Rem seem oblivious of the fact that both are based on the .308 Winchester. And writers of introductions to those cartridges in recent handloading manuals no longer mention that fact as though they came into being from outer space or miracle by their own means!

Neither of those two cartridges have the efficiency of their parent cartridge, nor it’s ultimate power and usefulness! For deer, coyote, hogs, maybe, but the .308 Winchester is a far more useful tool on large game – in other words it’s more versatile AND efficient!

Anytime a cartridge is “necked down” from its original, it becomes less efficient; and when it’s “necked up” it becomes more efficient. Consider those based on the historic .30-06: The .270 Win is not as efficient, nor does it have the upper end power or usefulness. I’ve owned a win 70 in .25-06, and handloads were made for every available bullet weight: a 120gr Partition maxed-out at 3100 fps from the 22″ barrel = 2560 ft-lbs. Plus, the SD of that bullet was only .260 with a BC of 391. I never shot a game animal with it, not even a ground hog! But it was a nice rifle, accurate and useless to me as an all-purpose rifle. It burnt more powder than a .308 Win but was less powerful and efficient. Etc.

If we want to consider one of the Weatherby Mags, like the .460, the ratio is about 1:67. Not as good as the .458, but better than a lot of other BIG-BORES because of bore size compared to chamber size. But you don’t get 8000 ft-lbs from your everyday rifle either!

Let’s look at a few more common cartridges used in everyday hunting for the likes of whitetails:

270 Win: 22″ barrel/150gr/2800 fps/2611 ft-lbs/55 grs powder = 47.5 ft-lbs per grain.

.30-06: 22″ barrel/ 180gr/2700 fps/2913 ft-lbs/60 grs powder = 48.5 ft-lbs per grain.

308 Win: 22″ barrel/165gr/2700 fps/2670 ft-lbs/42 grs powder = 63.5 ft-lbs per grain (very efficient).

6.5 Creedmoor: 22″ barrel/142gr/2700 fps/2298 ft-lbs/44 grs powder = 52 ft-lbs per grain.

• Those are average results from 22″ barrels.

• Some improvements are assumed from 24″ barrels – perhaps up to 50 fps.

• These results are based on NOSLER 9 which used a 24″ barrel for each. I reduced each by 50 fps.

• These don’t have a fudge factor, but perhaps many handloaders would complain over these results due to their “fudge factors”.

Perhaps each one could be slightly improved in efficiency, but that’s about average.

Of the rifles left in my locker, that I am still making handloads for, could be a bit more efficient through downloading them. And that’s generally true for any centerfire rifle. But I’ve always worked for best performance, not the least or minimal. Though some downloads have been used in my .458 as full power isn’t needed for both where and what I hunt. Though I’ve also wanted to know it’s limits, and I’ve found that out: About 6000 ft-lbs from a 400gr X-Bullet, a 500gr Hornady RN and a 350gr TSX. There were no undue stresses on the rifle. . . but that cannot be said about my body!

From the .458 about 5000 ft-lbs is plenty for any wild/dangerous creature from an excellent premium 300, 350, 400, 450 or 500gr in the right place!

Of course, those results are at the muzzles of each rifle. Downrange results will depend not only on the construction of the bullet and it’s placement, but also the bullets efficiency, or its BC. The question then is: will the impact velocity be sufficient for adequate bullet expansion? And, at what range?< A 250gr Nos. Part. launched from my 22-inch .35 Whelen. If Nosler’s .446 BC is nearly correct then at 500 yds 1834 fps/1867 ft-lbs should result at -42″. That’s better than the 225 AB at 2840 fps MV. An impact speed of 1834 fps should be adequate for full expansion, and 1867 ft-lbs should be adequate for a mature bull moose with good placement. Efficiency rating = 63 from 65 grs of CFE-223.

< From the 250gr TTSX in my 22″ .375 H&H. That’s over 100 fps faster than the 250 NP from my .35 Whelen, and with a similar .424 BC, it maintains velocity about as well, resulting in a slightly better trajectory and higher impact speed of 1881 fps and 1965 ft-lbs, at -39″. Efficiency rating = 57 from 77 grains of CFE-223. Using 77 grains of RL-17 under a 300gr the efficiency rate is 63 at 2700 fps.

The lighter the bullet is for most cartridges, the faster it will generally leave the muzzle – but there are some exceptions depending on IF there’s a suitable faster powder in burn rate to maximize MV for the chosen lightweight bullet in the chosen caliber. For example, in .458 Win the 300gr TSX or TTSX are worthy contenders for hogs to bull moose, or even Brown bear. But they have a relatively poor BC that means range is limited – especially the 300 TSX. And it’s tougher than its sibling 300gr TTSX with a larger cavity and poly tip. So for moose and grizzly, overall the 404gr Stone Hammer is the better/best choice. The 300 TSX/TTSX, 350 TSX and 404 SH should give adequate expansion at 400 yds when pushed to max velocities: about 2600 fps from the 404gr, 2800 fps from the 350 TSX and 2950 fps from the 300gr TSX/TTSX. But how many grizzlies will be shot at 400 yds? Or bull moose for that matter.

So efficiency can be manipulated to a certain extent for most big game cartridges, especially if you are a handloader. And efficiency is not intended to necessarily mean “more cheaply”. Read again the dictionary definition. Implied is the “best results” without unnecessary costs or labour. Efficient cartridges is normally expressed as energy per grain of gun powder, and we’ve presented some examples. Straight-wall cases and those nearly so are by far the most efficient, which also means the use of less powder for higher energy at less recoil, assuming other things are equal; i.e: barrel lengths, energy at the muzzle and PSI.

AND, btw, large, powerful magnums are among the most efficient: A 26″ .340 WBY is near the top in that regard: 2727 fps from a 300gr Nosler ABLR from 75 grs of IMR4350 =4953 ft-lbs =66 efficiency rating! That’s right up there with the .460 WBY, and much more than your typical deer rifle!!

Hummmm . . . . If only I were 50 again!

Till the next . . . . .

Shalom

BOB MITCHELL