With reloading supplies still difficult to come upon are efficient cartridges the smart choice right now?
Have you ever let the efficiency of a cartridge dictate your firearm purchase? Does cartridge efficiency weigh on your mind? With the scarcity of reloading components, those cartridges that give the most “bang for the buck,” quite literally, have a bit more appeal.
I’ve recently had conversations with fellow reloaders who are reaching for their .308 Winchester instead of their .300 Winchester Magnum due to the fact that the former burns so much less powder than the latter.
Sweating The Small Stuff
Each cartridge will require a primer, so there’s no savings there, but powder consumption can make a considerable difference, especially when you compare those larger-cased magnum cartridges to the standard designs.
Looking into the example above, and using the 165- to 168-grain bullets so popular for hunting and target work, Nosler’s excellent load data shows the .308 Winchester will require a powder charge somewhere between 37 and 38 grains on the low end, to as much as 52 grains with slower powders and a severely compressed load.
The speedier .300 Winchester will need somewhere between 58 grains on the low end and can handle up to 80 grains of certain powders at the top end. There are 7,000 grains in a pound of powder, so the .308 Winchester will give between 189 and 134 shots to the pound, and the .300 Winchester Magnum will give between 120 and 87 shots to the pound. For a target shooter trying to maximize their powder supply, this may make a significant difference.
It’s no great secret that the .308 Winchester has long been considered one of our most efficient cartridges, giving a lot of field performance from a small case with a relatively light powder charge … and it can even burn that charge in a short barrel.
Now, the .300 Winchester Magnum will better the .308’s velocity by 400 fps in some instances, but that doesn’t mean that the .308 isn’t useful. In fact, the .308’s velocity—somewhere in the 2,750- to 2,850-fps range with the 165-grain bullet—makes a perfectly sound hunting choice. Furthermore, at the most common hunting distances, this velocity poses no handicap at all. If the better powder efficiency means more time at the range or helps to extend your powder supply, the more efficient cartridge may be the better choice.
Defining What An Efficient Cartridge Is
An efficient cartridge is one that gives a proper balance of usable striking power, flat trajectory and minimal powder charge. For example, the .416 Rigby uses somewhere between 90 and 100 grains of powder to drive a 400-grain bullet to the desired muzzle velocity of 2,400 fps, where the smaller-cased .416 Remington Magnum can achieve the same results with 70 to 80 grains of powder.
Yes, the .416 Remington needs to run at a higher pressure to get the same speeds, but that has been proven to be a non-issue; I’ve used that cartridge with full-house loads in 100-plus degree temperatures with no pressure problems. That powder efficiency and the ability to fit more of the slimmer cases in a rifle’s magazine are the features that attracted me to the Remington over the Rigby.
The .22-250 Remington is my absolute favorite varmint/predator cartridge, but I can’t defend it as an efficient cartridge, especially when comparing it to the .223 Remington. Much like the comparison of the .308 Winchester and .300 Winchester Magnum, the .22-250 will better the velocity of the .223 by a considerable amount—nearly 500 fps with a 55-grain bullet—but the .223 has a very usable velocity and trajectory.
Looking at Hodgdon’s CFE223, one of the powders common to both cartridges and one which gives excellent velocity in both, the .223 will top out at 28 grains and the .22-250 will top out at 39 grains. While gaining 500 fps for an 11-grain increase in powder can seem like a good trade-off considering the fact that you get 70 more shots to the pound when shooting a .223, still holding a cartridge generating over 3,000 fps with that 55-grain bullet may have you rethinking the decision.
The 7mm Remington Magnum is a very popular hunting choice. Still, I’ve long felt that the cartridge is inefficient in a couple of ways from a handloader’s point of view. Firstly, it is, was and always will be overbore, meaning the case capacity compared to the bore diameter is such that we may have reached the point of diminishing returns.
Comparing case families, I’ve always noted that the .300 Winchester Magnum has historically shown a much greater advantage over the .30-06 Springfield than the 7mm Remington Magnum over the .280 Remington. Depending on the load data you look at, you’ll see the .280 delivering velocities within 100 fps of the larger 7mm Mag., and quite often in a shorter barrel length. You’ll see a 10-grain difference between the two cartridges, so the .280 Remington makes all kinds of sense, from an efficiency standpoint.
Stretching Your Powder
For those who are unable to switch cartridges or simply have no desire to do so, there are some steps you can take to maximize accessible powder supplies.
Generally speaking, with regard to rifle cases, the faster-burning powder choices within a given list of applicable powders for certain cartridges will require the least amount of powder. As an extreme example, my .470 Nitro Express traditionally runs on powders that require a charge weight of between 103 and 118 grains of powder to arrive at the magic 2,150-fps muzzle velocity. I found good data with Reloder 15 powder—with a much faster burn rate than the rest of the lot—which uses a range of charge weights between 87 and 90 grains. However, it needs a foam wad to compact the load for uniform velocities.
I like IMR4350 in the .30-06 Springfield, but IMR4064 will go further in that case. In the .270 Winchester, Reloder 22 is a fantastic choice, but like the .30-06, IMR4064 or IMR4166 might get better mileage.
For the pistol crowd, Hodgdon’s TiteGroup is a powder specifically engineered to have low charge weights while delivering respectable velocities. The .38 Special will push a 158-grain cast lead bullet to 930 fps with just 3.8 grains, and the .45 Colt will send the 250-grain slugs to just over 900 fps in my beloved Ruger BlackHawk.
I’m optimistic that the supply drought will start to ease up in the coming months, but the lesson has been learned. We, as reloaders, need to maximize the efficiency of our supplies, and sometimes that requires rethinking the approach we take to reloading.
Editor’s Note: This article originally appeared in the August 2021 issue of Gun Digest the Magazine.