Most "efficient" cartridge for each caliber?

[Varminterror]

Well YOU know that, and I know that, but for someone getting into firearms hunting and looking at a dizzying array of choices, a $5 app that might help them select could be useful.

You’d have an app which recommends something like the 350 Legend or 450 bushmaster as the “most efficient” cartridge for deer hunting… is that a quality recommendation to make to unwitting new deer hunters?

 

[Newtosavage]

You’d have an app which recommends something like the 350 Legend or 450 bushmaster as the “most efficient” cartridge for deer hunting… is that a quality recommendation to make to unwitting new deer hunters?

LOL.

If it's a ****ty app design, then yea, that might happen.

 

[jmorris]

So I wonder if there is a "most efficient" cartridge for each bore size, and if so, what is it? Surely with all the various rounds developed for each bore, one could map this out if not from real world experience, then just academically from published load data.

I think it’s doable. What is the equation we are going to use to define “efficient?”

Ft/lbs of energy per grain of powder?

 

[someguy2800]

That comparison only works if you used propellants with similar burn speeds and temperatures.

The most efficient cartridge will be the one with the largest ratio of charge weight to area under the pressure curve.

Let me know which propellent is suitable for a 220 swift and a 22 lr.

 

[someguy2800]

You’d have an app which recommends something like the 350 Legend or 450 bushmaster as the “most efficient” cartridge for deer hunting… is that a quality recommendation to make to unwitting new deer hunters?

If you program it to return results at the muzzle then yes, but not if you program it to return results at some range such as 100, 200, 300 yards, ect... Then you have to expand it to not only cartridges but bullet selection, or at least some reasonable average of available ballistic coefficients.

 

[Newtosavage]

I think it’s doable. What is the equation we are going to use to define “efficient?”

Ft/lbs of energy per grain of powder?

Any tool would only work if it allowed the user to define some parameters. A half dozen sliders that let someone choose their min/max would narrow things down quickly.

What are the parameters that are important to most people?

Tolerable recoil
Velocity
Bullet weight
Bullet diameter

Set limits on those and you'll be on your way.

 

[someguy2800]

I honestly think it would be a fun app if someone developed it. I find myself all the time flipping through my load books or on my phone looking at load data for cartridges I don't own and comparing different things in ballistic calculators. It would be neat to be able to select 4 or 5 calibers and enter a few perameters such as bullet, rifle weight, maybe barrel length, and seeing a visual comparison of recoil, downrange energy, drop and drift, ect... We get questions on here all the time about people asking what is the difference in recoil or range or whatever between a 6.5C and 7-08 or whatever, so why not make an app to show visual comparisons? I think it would help a lot of new shooters make more educated decisions.

 

[Steve S.]

I had a dream about physical efficiency the other night - like all dreams, it was garbled and disconnected. All I remember is an angel leading me to a forest with three trees, then crossing a river onto grassy plains with no trees and then crossing a final river into a forest having eight trees. I do know that the dream meant something wonderful and magic, something proven, royal and majestic however, I am still trying to decode the ultimate meaning.

 

[someguy2800]

I had a dream about physical efficiency the other night - like all dreams, it was garbled and disconnected. All I remember is an angel leading me to a forest with three trees, then crossing a river onto grassy plains with no trees and then crossing a final river into a forest having eight trees. I do know that the dream meant something wonderful and magic, something proven, royal and majestic however, I am still trying to decode the ultimate meaning.

I am something of a dream decoder myself. I think it means you should buy a new Christensen Arms Ridgeline in 280 Ackley.

 

[jmorris]

What are the parameters that are important to most people?

Tolerable recoil
Velocity
Bullet weight
Bullet diameter

Set limits on those and you'll be on your way.

I agree, just killing time without defining what we are talking about. I would put some of the primer compound only propelled .22 rounds up against the latest and greatest wiz bang rounds out there if we used ft/lbs per grain of powder. Even if it’s only a few ft/lbs of energy, using 0.0 grains of powder, they would win everytime.

 

[Varminterror]

If you program it to return results at the muzzle then yes, but not if you program it to return results at some range such as 100, 200, 300 yards, ect... Then you have to expand it to not only cartridges but bullet selection, or at least some reasonable average of available ballistic coefficients.

Adding longer and longer range to the energy requirements just lengthens the case - 45acp or 450bm becomes 45-70 or 458wm, 9mm or 350L becomes 375win… but the trends remain - low expansion ratios, small cases, big bores, high operating pressures.

 

[Varminterror]

I think it’s doable. What is the equation we are going to use to define “efficient?”

Ft/lbs of energy per grain of powder?

This is really the only metric for cartridge efficiency which could make sense. (Kinetic) Energy Out = n * (Potential) Energy In. Greatest n wins.

Otherwise, it’s just a bunch of subjective preferences being concealed within mathematical algorithms and user limit inputs.

 

[Grumpy_old_Fart]

First, set a standard.

Without a standard, a baseline, any testing is moot.

 

[someguy2800]

Adding longer and longer range to the energy requirements just lengthens the case - 45acp or 450bm becomes 45-70 or 458wm, 9mm or 350L becomes 375win… but the trends remain - low expansion ratios, small cases, big bores, high operating pressures.

Again, that would only be true if the metric you choose to compare is at the muzzle or a reflectively short range, a If you choose to compare energy at some range selected by the user, then at some point external ballistic efficiently wins over internal ballistic efficiency. Say for example I choose to search like the OP suggested for the best energy with a bullet weight between 100-180 grains and a max free recoil of 21 ft lbs in an 8 lb gun. If you chose to sample the energy at the muzzle or 50 yards you will get a straight wall of some sort, but if you choose to sample the energy at 600 yards you will get a smaller caliber high BC result, and at 200 yards something in between.

 

[Newtosavage]

Yea, min-max distance could be another slider.

Like you someguy, I'd use it. And I don't really even need it. But it would be pretty cool to play with. I think it would open a lot of eyes too.

 

[Double Naught Spy]

When the bullet uncorks the barrel, the energy stored in the compressed gas behind it is lost to propulsion. The lower the pressure at bullet exit, the higher the efficiency.

No, not for shooting purposes. There is definitely a point of diminishing returns. If the pressure is just 1 PSI at bullet exit, the bullet isn't going very far or very fast and so is not useful, although that would be the most efficient load to get the bullet out of the barrel itself. In other words, that would be just above a squib load.

 

[Newtosavage]

First, set a standard.

Without a standard, a baseline, any testing is moot.

One would think that by now, with billions of rounds having been fired and thousands of cartridges developed, there would be some kind of standard for efficiency.

 

[redneck2]

If you REALLY want “efficient” cartridges, you simply use the smallest powder charge that will squirt the projectile out of the muzzle. The most efficient hands down is a .22 short. I have been told that it only uses the primer for propellent and little or zero added powder.

Since a .22 short is deemed less than adequate for anything larger than small vermin, we trade inefficiency for performance

You can usually figure a 25% increase in powder charge gives a 10% increase in velocity.

If one was really interested in efficiency, you’d be driving a Prius instead of a 1/2 ton pickup

Back about four or five lifetimes ago I was an Area Service Manager for Deere & Co. I had a couple different guys that tried to convince me that we should make an electric vehicle that charged itself off power from the rear wheels as it was moving. I tried to explain that it would take more energy to turn the internal generator than the generator provided. They couldn’t comprehend it.

 

[Newtosavage]

If you REALLY want “efficient” cartridges, you simply use the smallest powder charge that will squirt the projectile out of the muzzle. The most efficient hands down is a .22 short. I have been told that it only uses the primer for propellent and little or zero added powder.

Since a .22 short is deemed less than adequate for anything larger than small vermin, we trade inefficiency for performance

You can usually figure a 25% increase in powder charge gives a 10% increase in velocity.

If one was really interested in efficiency, you’d be driving a Prius instead of a 1/2 ton pickup

Back about four or five lifetimes ago I was an Area Service Manager for Deere & Co. I had a couple different guys that tried to convince me that we should make an electric vehicle that charged itself off power from the rear wheels as it was moving. I tried to explain that it would take more energy to turn the internal generator than the generator provided. They couldn’t comprehend it.

Well, we do have one of each in our garage. LOL

Okay, maybe efficiency isn't the right word. Maybe it's the best we can do is identify an "optimal" cartridge or group of cartridges for each bore and each job. That's where the user-defined parameters would come in. Plug in some ranges, and have this app or tool spit out a bell curve showing which cartridge makes the most sense.

Or, have a cartridge selection option that allows you to compare two cartridges directly, or a group of cartridges, as you adjust the sliders to set the parameters.

I still think it would be an interesting, if not useful, tool. I'd probably waste far too much time on it. LOL

 

[CoalTrain49]

Well YOU know that, and I know that, but for someone getting into firearms hunting and looking at a dizzying array of choices, a $5 app that might help them select could be useful.

People are using apps for almost everything these days. Input x and you get y without thinking too much about it. It's a lifestyle that many younger people have adopted. I know a young couple (college grads) with two kids, ages 1 and 3 that use an app to track their kids sleep patterns. Once they have enough information to formulate things like the best nap and bed time they put the kids on that schedule because the app determined that to be optimal.

So I can see some millennial who has zero experience with cartridges/hunting/shooting inputting a bunch of information into an app and buying a rifle chambered in a cartridge that the app recommended. That might be better than asking sumdude behind a gun counter with tats on his neck and a ring in his ear.

How many times have we seen questions on these forums like what's the best cartridge for deer?

 

[Varminterror]

No, not for shooting purposes. There is definitely a point of diminishing returns. If the pressure is just 1 PSI at bullet exit, the bullet isn't going very far or very fast and so is not useful, although that would be the most efficient load to get the bullet out of the barrel itself. In other words, that would be just above a squib load.

This is a false assumption.

Recall, the pressure at the muzzle is only the result of the remaining force after expansion of the propellant gases. The bullet has already been accelerated, such it has a certain velocity, and all remaining pressure which exceeds the drag force imparted by the bore on the bullet remains an accelerating force. It’s fair to assume 1psi isn’t sufficient to overcome bore friction, but it’s not fair to assume that the bullet will have decelerated to the point of ineffectiveness. Expansion ratio, maximum in-bore inertia, and bore drag will dictate how much the bullet is decelerated as the driving force falls below that of the drag force (reminding, the slower the bullet goes, the less drag force it experiences, so it’s a differential system). If a small case pushes a bullet with a short bearing surface to 4000fps in bore, it could potentially still have greater than 2k muzzle velocity in an exceptionally long barrel even if the muzzle pressure has reduced to near-atmospheric pressure.

 

[Speedo66]

First, set a standard.

Without a standard, a baseline, any testing is moot.

This! I see it as having a set barrel length and target velocity for a given caliber, then see which cartridge case gets you there with the least amount of powder.

 

[Grumpy_old_Fart]

What would the baseline goal look like?
2600-2900 fps?
100-180 gr bullet?
243-338 cal?
Case length? (For action length discussion)
Powder burn rate?
Barrel length?
Base cartridge availability?

Edited to add:
accuracy requirement?
barrel Twist rate?

 

[Varminterror]

Again, that would only be true if the metric you choose to compare is at the muzzle or a reflectively short range, a If you choose to compare energy at some range selected by the user, then at some point external ballistic efficiently wins over internal ballistic efficiency. Say for example I choose to search like the OP suggested for the best energy with a bullet weight between 100-180 grains and a max free recoil of 21 ft lbs in an 8 lb gun. If you chose to sample the energy at the muzzle or 50 yards you will get a straight wall of some sort, but if you choose to sample the energy at 600 yards you will get a smaller caliber high BC result, and at 200 yards something in between.

This is an example of the over-defined system I described - it’s applying interdependent variables as independent input constraints. Both 600 yard energy AND recoil energy are dependent upon muzzle energy - so sure, the algorithm can be written, but it’s a trivial exercise, again, yielding an empty set - an output without true value. In effect, it’s defining the answer by overconstraining the question, such the question isn’t a question.

 

[codytrucker]

The most efficient cartridge is the one that does the job at hand , reliably, with the least amount of brass , lead , copper ,and powder .To my mind Karamojo Bell's .275 Rigby ,or some poachers 7.62x39 , are the most meaning full efficient cartridges to date .

The only cartridges I know of that really seem to get ahead on efficiency seem to be the '06 Ackley cartridges , loaded with the same powder and bullet , at the same pressure they seem to do the same as belted magnums with less powder . As long as barrel length is under 26 inches. But this is from loading manuals and internet info , i don't have the rifles and equipment to test it out myself . I'd like to see a real world comparison between a 6.5-06 A and a 264 win , same components ,both at 65,000 psi , and a 280 A ,using 270 win brass for strength , again at 65,000 psi against a 7mm rem .