What are the most EFFICIENT rifle cartridges?

[ve7poi]

338 federal- 200 grain bullet @2700fps

I’ve used the 185 tsx it get the job done from wild boar b bear kudu gemsbuck blk wildebeest blue wildebeest zebra etc one shot kills

Now have a 475 Turnbull would love to try on game one day ( ruger #1 and win lever gun)

 

[DaddyFlip]

To expound on my previous waffling, here's some actual efficiency percentages based on the data I showed above.

View attachment 732623

I didn't plan on doing any work on this, but then my fountain pen pal decided to go all technical on the topic. It will take a bit of time to provide my data answer due to work obligations, but I've already started and will provide a preview of the "ground rules" I mentioned earlier in the thread:

• @Alistair the difficulty with your data is you have no dependent variable; this is why your calculated efficiency is increasing with increasing bullet weight, which invalidates the output. You are holding the powder type constant, but it is not a variable in the equation. The variables are: bullet weight, powder charge, and velocity. One of these has to be held constant. Given the tabulated data we have to work with, the only one that can be held constant is the bullet weight.
  • A secondary difficulty is the Hornady load book which gives rough velocity ranges with no indication of pressure. The best thing it provides is technical data of it's own bullets. I have found that the powder companies, especially Hodgdon, provides the best comparative data.
  • Varget is a good powder type to span the entire caliber range without restricting bullet weight, but we have to select powder types that are typical of the largest range of hunting cartridges of interest.
• This means we have to constrain the cartridge selection such that the powder type AND bullet weight spans a cartridge range of interest.
  • Example preview #1: Using Hodgdon load data, select 300gr bullet as the dependent variable and compare cartridges using constant powder types H4350 and H4831 which gives a four-caliber cartridge range of 338 Win Mag to 416 Rigby. Calculate the energy and divide by the powder charge to get a relative efficiency calculation sorted in descending order.
  • Example preview #2: Repeat Ep#1 with 150gr bullet as the dependent variable with the same constant powder types which gives a cartridge range of 6.5CM to 8mm Rem Mag. Mix these in with the 300gr bullet results to get an overall efficiency ranking.
  • Repeat this process with several other bullet weights of hunting interest and compile two lists: one list dependent on powder type; the other list independent of powder type.
• What you find from the preliminary results are the following (preview):
  • At equal bullet weight, smaller calibers tend to be more energy efficient than larger calibers (nearly the opposite of @Alistair conclusion, which says that if bullet energy is the most important thing, choose the smallest caliber that provides the bullet weight and energy needed for the task.
    • The following example will illustrate this point: In my tabulated calculations SO FAR from 150gr 6.5CM to 300gr 416 Rigby, a 300gr 33 Nosler is the most energy efficient cartridge with H4350 and the third most efficient with H4831. But change the bullet weight to 180gr and it becomes equally efficient to the 300 Weatherby and... the 30-40 Krag! BUT at almost double the energy of the Krag! This is why efficiency across caliber classes is near to completely meaningless.

That's all the preview commentary for now. I've completed a large chunk of cartridge calculations and will share when I can get to it, along with more detailed ground rules. Goodnight all!

PS Edit: My parting shot is that there are other variables that are changing that aren't in the equation... (1) case design + case volume + caliber is what we are comparing; (2) bullet design/MOC, seating depth/OAL, and barrel length we have to account for OR assume we can ignore differences in these. This is where the powder data is better than the bullet data in most cases. Finally, because we are using static tabulated data, we have to assume we can compare maximum charge and velocity shown is at maximum safe pressure at all times (or at least that the maximum charge and velocity can be compared across all loadings). Again, it's an academic exercise for fun, but I think it will verify things people already know logically or from experience (or apathy haha).

 

[OldCombatEngr]

By efficient, I mean which cartridges move a bigger bullet with less powderl, while providing greater velocity without increased powder capacity. For example, a 30'06 will move an equal weight of bullet faster and with less pressure than a 270 with equal loading, while a 35 Whelen will move a bigger bullet than the 30'06 at velocity for the heavy weight that the 30'06 can't match without exceeding safe pressure. (as well as the '06 requiring more powder to try and match it)
It seems to me that the more a cartridge is necked down, the less efficient it becomes? Yet we can't all just shoot straight walls, can we?
I also sometimes confuse a "balanced load" with an efficient load. A 7X57 is balanced--recoil is such that you could probably shoot it off your chin, yet it is a great killer in the field. But an 8x57 can launch a bigger payload (though with more recoil) and a 9.3X57 greater still. Is this why the 358 Win. is so good in performance?

What are your votes for most efficient cartridges? This may accidentally or otherwise pit magnums vs non-magnums.

Check out some of the discussions of expansion ratios for supplementary "scientific" explanations: https://reloader.com/2024/08/volume-expansion-ratio-explained/

 

[steve white]

I didn't plan on doing any work on this, but then my fountain pen pal decided to go all technical on the topic. It will take a bit of time to provide my data answer due to work obligations, but I've already started and will provide a preview of the "ground rules" I mentioned earlier in the thread:

• @Alistair the difficulty with your data is you have no dependent variable; this is why your calculated efficiency is increasing with increasing bullet weight, which invalidates the output. You are holding the powder type constant, but it is not a variable in the equation. The variables are: bullet weight, powder charge, and velocity. One of these has to be held constant. Given the tabulated data we have to work with, the only one that can be held constant is the bullet weight.
  • A secondary difficulty is the Hornady load book which gives rough velocity ranges with no indication of pressure. The best thing it provides is technical data of it's own bullets. I have found that the powder companies, especially Hodgdon, provides the best comparative data.
  • Varget is a good powder type to span the entire caliber range without restricting bullet weight, but we have to select powder types that are typical of the largest range of hunting cartridges of interest.
• This means we have to constrain the cartridge selection such that the powder type AND bullet weight spans a cartridge range of interest.
  • Example preview #1: Using Hodgdon load data, select 300gr bullet as the dependent variable and compare cartridges using constant powder types H4350 and H4831 which gives a four-caliber cartridge range of 338 Win Mag to 416 Rigby. Calculate the energy and divide by the powder charge to get a relative efficiency calculation sorted in descending order.
  • Example preview #2: Repeat Ep#1 with 150gr bullet as the dependent variable with the same constant powder types which gives a cartridge range of 6.5CM to 8mm Rem Mag. Mix these in with the 300gr bullet results to get an overall efficiency ranking.
  • Repeat this process with several other bullet weights of hunting interest and compile two lists: one list dependent on powder type; the other list independent of powder type.
• What you find from the preliminary results are the following (preview):
  • At equal bullet weight, smaller calibers tend to be more energy efficient than larger calibers (nearly the opposite of @Alistair conclusion, which says that if bullet energy is the most important thing, choose the smallest caliber that provides the bullet weight and energy needed for the task.
    • The following example will illustrate this point: In my tabulated calculations SO FAR from 150gr 6.5CM to 300gr 416 Rigby, a 300gr 33 Nosler is the most energy efficient cartridge with H4350 and the third most efficient with H4831. But change the bullet weight to 180gr and it becomes equally efficient to the 300 Weatherby and... the 30-40 Krag! BUT at almost double the energy of the Krag! This is why efficiency across caliber classes is near to completely meaningless.

That's all the preview commentary for now. I've completed a large chunk of cartridge calculations and will share when I can get to it, along with more detailed ground rules. Goodnight all!

PS Edit: My parting shot is that there are other variables that are changing that aren't in the equation... (1) case design + case volume + caliber is what we are comparing; (2) bullet design/MOC, seating depth/OAL, and barrel length we have to account for OR assume we can ignore differences in these. This is where the powder data is better than the bullet data in most cases. Finally, because we are using static tabulated data, we have to assume we can compare maximum charge and velocity shown is at maximum safe pressure at all times (or at least that the maximum charge and velocity can be compared across all loadings). Again, it's an academic exercise for fun, but I think it will verify things people already know logically or from experience (or apathy haha).

Yeah, yeah, that's what I was going to say (...as you guys go completely over my head....) lol

 

[DaddyFlip]

Yeah, yeah, that's what I was going to say (...as you guys go completely over my head....) lol

Actually, we're in "dumb" phase at the moment; meaning, we might not know what we're talking about. I like playing with numbers to see what info I can squeeze out of them. Somebody somewhere in time has already done this work and given the right answer, it's just I prefer to roll around in the mud looking for an acorn rather than pick the low hanging fruit.

 

[Mark A Ouellette]

Yeah, yeah, that's what I was going to say (...as you guys go completely over my head....) lol

As an academic exercise one could calculate data on top of data! But unless one is loading commercially many thousands of the same cartridge and must do everything possible to reduce costs, why bother?

For my .416 Taylor, Rem, and fat old Rigby, obviously the Taylor is most efficient to achieve a 400 gr projectile at 2300 fps. At 2400 fps, the Taylor might do that with one or two powders. For 2500 fps, the Rigby stands alone.

Now let's get serious! The weight of powder is included in the ejecta which is a factor in the recoil formula.

SAAMI: https://saami.org/technical-information/recoil-formulae/

There are many recoil calculators available online that require the grains of powder. Here's what I use,

ShootersCalculator.com | Recoil Calculator

An online calculator that calculates the recoil energy, impulse, and velocity of a firearm according to the firearm's weight, powder charge, bullet weight, and bullet muzzle velocity.

shooterscalculator.com

If however I want to shoot a .416 Rigby that I know has more recoil for a 400 gr bullet at 2400 fps than the Rem cartridge, I will try a faster burning powder.

The attached excerpt from LoadData dot com quickly provides information for 2400 fps loads by powder and its weight. If I want a temperature stable powder, although not as necessary with the lower pressure .416 Rigby than the higher pressure .416 Rem, temperture stable H4350 produces over 2400 fps with 93 grains. Other powders require over 100 grains. Since I have a few pounds of H4350 on hand, problem solved!

If one handloads for many different cartridges, I highly recommend subscribing to LoadData dot com!

Note: I don't usually post printed information online because of copyrights but is this case, maybe it's advertising for LoadData dot com !

 

[rdog]

By efficient, I mean which cartridges move a bigger bullet with less powderl, while providing greater velocity without increased powder capacity. For example, a 30'06 will move an equal weight of bullet faster and with less pressure than a 270 with equal loading, while a 35 Whelen will move a bigger bullet than the 30'06 at velocity for the heavy weight that the 30'06 can't match without exceeding safe pressure. (as well as the '06 requiring more powder to try and match it)
It seems to me that the more a cartridge is necked down, the less efficient it becomes? Yet we can't all just shoot straight walls, can we?
I also sometimes confuse a "balanced load" with an efficient load. A 7X57 is balanced--recoil is such that you could probably shoot it off your chin, yet it is a great killer in the field. But an 8x57 can launch a bigger payload (though with more recoil) and a 9.3X57 greater still. Is this why the 358 Win. is so good in performance?

What are your votes for most efficient cartridges? This may accidentally or otherwise pit magnums vs non-magnums.

I have a 6mm arc with a 65 grain Hornady vmax bullet 29 g of ww748 24 inch bbl =3325 fps & a 6.5 Grendel 120grain Taipan bullet 28 grains of WW748 =2765 fps 24 inch bbl, i class these as efficient cartridges,as they use less than 30 grains of propellant.

 

[DaddyFlip]

I'm amazed at how much time I can waste when I really set my mind to it! This is for you @steve white, even though I know you were more interested in seat of the pants, real-world experience and/or opinion. Also for you @Alistair because I appreciate the theory discussion in your initial effort; I think you were on to something. I was able to build the efficiency calculation database AND get my work done today. My ground rules were:

• Use all Hodgdon powders using their load data (for consistency); assume that Hodgdon's data is accurate, that there is no "agenda" behind their data, and that their max loads represent the highest powder charge without going over SAAMI pressure limit
• Use as many hunting calibers as possible from the well-known ones to some that I've heard mentioned on this site from time to time; throw in a couple of benchrest carts for comparison
• Only allow carts where the test data indicates a 24-inch barrel (again, for consistency); this left out several Weatherby carts and the 308 Norma Mag (26") and the 300 Savage (22")
• Don't pick and choose powders/bullets/weights; pull EVERYTHING from the load data and let the spreadsheet sort it out (removes bias and lets us find the needle in the haystack); there are 3,636 loads represented.

Here are the 73 cartridges I selected for the database. It is easy to add others if anyone has a request (must be in Hodgdon's load data to qualify):

And here are the 24 Hodgdon powders represented:

All I have time for tonight is highlights after the overall sort. This is energy efficiency, so
(Bullet weight x velocity^2)/450436 = KE/Powder Charge = Ft.lb/grain = Efficiency

• Various loadings from 5 cartridges took the Top 26 spots: 460WBY, 458WM, 405Win, 45-70, 308Win. Notice three of those are straightwall, so whoever was first to suggest that is a winner
  • The most energy efficient load of all was the 460WBY pushing a 600gr Barnes RN to 2439fps with 104gr of H4350 (E=76.2)
  • The most energy efficient 308Win was a 210gr Berger VLD Hunter at 2276fps over 34.7gr of Benchmark
• The top 64 spots were held by 8 cartridges; joining the Top 5 were the 338-06, 338RCM, and 416 Rem Mag
• In last overall place with E=27.0 was the 30-40 Krag trying to push a 100gr Hornady SP with 51gr of H4350 to 2492fps

When vacation starts at the end of the week, I'll be able to sort by caliber, powder, cartridge, bullet, etc. and answer specific questions if anybody cares (probably not). It's a Google Sheet so I don't mind sharing if anyone is interested (probably not).

 

[NIGHTHAWK]

.243 Winchester - 80 Grain Barnes TTSX

 

[Boone66]

The Bore-Ratio is why a ‘06, 338-06, or Whelen can push a heavier weight bullet faster than its counterpart.

IMO a 6GT, Dasher or 22 ARC would be considered just as efficient when going smaller diameter in bullet size.

Just as a 300 Norma Magnum is far more efficient in pushing heavy 230-245 grain bullets faster than a 30-378 Wby. Which requires 20 grains more powder to do the same velocity.

I noticed this with the 300 Rum and 300win also, I really hadn't noticed, before, but I was doing load tests at the same time. With 190-210 bullets.

 

[Boone66]

I have a 35 Brown-Whelen I’m hopefully going to start playing with when the weather is warmer, essentially a 280 ai necked up to 35. It’s supposed to push the same bullets as the Whelen 200 or 300 fps faster, we’ll see.

I have plans for one of these, I'm really interested in what you find out.

 

[DaddyFlip]

Here are the 73 cartridges in order of average efficiency of all loads listed in the Hodgdon load data. The first column COUNTA is the number of loads listed; the other columns should be self-explanatory. That's all for now; enjoy!

 

[steve white]

Here are the 73 cartridges in order of average efficiency of all loads listed in the Hodgdon load data. The first column COUNTA is the number of loads listed; the other columns should be self-explanatory. That's all for now; enjoy!
View attachment 732992View attachment 732993

Well, that is just about the definition of "counter-intuitive". Thanks for all the work!

 

[Brickman301]

The 375 winchester is about the winner .It pushes a 220 gr bullet at 2400 fps with about 37 grs powder .I love this little cartridge in win 94 bb weighing only 6 pounds with very little kick .The 338 federal is also another one 50 grs powder to move a 200 gr bullet 2600 fps .

375 Winchester is a new to me cartridge. I picked up a Winchester 94 big bore a few months ago.
Haven’t messed with it yet, but plan to after the deer season ends here. It’s basically an updated 38-55.
I have already picked up reloading dies and a bullet mold. Still need to pick up some brass, and gas checks. I’m very excited to start messing with this rifle/ammo.
And yes, it seems to be a very efficient cartridge.

 

[DaddyFlip]

It will make more sense and be more fun when we list the rankings by bullet weight or by caliber I just wanted to post something quickly. The 458 comes out on top overall for two reasons number one it's a straight wall cartridge so bore ratio comes into effect and number two it has a small spread of bullet weight only a 25% increase from smallest to largest 400 grain to 500 grain. Cartridges like the 460 and the 30-06 double their weight from low to high. The 460 span is 300 to 600 and the 30-06 span is 110 to 220. Energy efficiency is usually going to favor the heavier bullets so cartridges with a wide span will have their overall efficiency dragged down.

 

[DaddyFlip]

375 Winchester is a new to me cartridge. I picked up a Winchester 94 big bore a few months ago.
Haven’t messed with it yet, but plan to after the deer season ends here. It’s basically an updated 38-55.
I have already picked up reloading dies and a bullet mold. Still need to pick up some brass, and gas checks. I’m very excited to start messing with this rifle/ammo.
And yes, it seems to be a very efficient cartridge.

I will add this cartridge and see where it lands.

 

[Boone66]

I actually thought the 9.3x74R would have placed higher, interesting results

 

[Noah_McCoy]

I remember seeing an interview with John Lazzeroni where he described his 30 cal short magnum based on the rigby case. He seamed to think the short fat case created a sort of combustion chamber so not all the powder had to be burned down the bore.

 

[Alistair]

I'm amazed at how much time I can waste when I really set my mind to it! This is for you @steve white, even though I know you were more interested in seat of the pants, real-world experience and/or opinion. Also for you @Alistair because I appreciate the theory discussion in your initial effort; I think you were on to something. I was able to build the efficiency calculation database AND get my work done today. My ground rules were:

• Use all Hodgdon powders using their load data (for consistency); assume that Hodgdon's data is accurate, that there is no "agenda" behind their data, and that their max loads represent the highest powder charge without going over SAAMI pressure limit
• Use as many hunting calibers as possible from the well-known ones to some that I've heard mentioned on this site from time to time; throw in a couple of benchrest carts for comparison
• Only allow carts where the test data indicates a 24-inch barrel (again, for consistency); this left out several Weatherby carts and the 308 Norma Mag (26") and the 300 Savage (22")
• Don't pick and choose powders/bullets/weights; pull EVERYTHING from the load data and let the spreadsheet sort it out (removes bias and lets us find the needle in the haystack); there are 3,636 loads represented.

Here are the 73 cartridges I selected for the database. It is easy to add others if anyone has a request (must be in Hodgdon's load data to qualify):

View attachment 732923

And here are the 24 Hodgdon powders represented:

View attachment 732924

All I have time for tonight is highlights after the overall sort. This is energy efficiency, so
(Bullet weight x velocity^2)/450436 = KE/Powder Charge = Ft.lb/grain = Efficiency

• Various loadings from 5 cartridges took the Top 26 spots: 460WBY, 458WM, 405Win, 45-70, 308Win. Notice three of those are straightwall, so whoever was first to suggest that is a winner
  • The most energy efficient load of all was the 460WBY pushing a 600gr Barnes RN to 2439fps with 104gr of H4350 (E=76.2)
  • The most energy efficient 308Win was a 210gr Berger VLD Hunter at 2276fps over 34.7gr of Benchmark
• The top 64 spots were held by 8 cartridges; joining the Top 5 were the 338-06, 338RCM, and 416 Rem Mag
• In last overall place with E=27.0 was the 30-40 Krag trying to push a 100gr Hornady SP with 51gr of H4350 to 2492fps

When vacation starts at the end of the week, I'll be able to sort by caliber, powder, cartridge, bullet, etc. and answer specific questions if anybody cares (probably not). It's a Google Sheet so I don't mind sharing if anyone is interested (probably not).

Well done. A much more comprehensive methodology!

One build for you.

If you're comparing disparate powders, then I take some issue with your calculation relying on grains.

You need to account for variation in specific energy per grain for each powder as it's 'possible' that this might vary very widely, with some powders being a lot less energy dense.

Hence, efficiency should be:

Powder energy content:

Specific KJ/Kg powder / 15432.4 = KJ/grain.

KJ/grain * # grains = KJ chemical energy in propellant charge.


Bullet energy:

((Bullet weight * V^2)/450426) * 0.00135582 = bullet kinetic energy in KJ.



(Kinetic energy in bullet / Chemical energy in powder) *100 = % efficiency.

Doing it this way, you'll see much lower % efficiency numbers, replicating that 20-35% range I had in my little table. This makes more intuitive sense as well: You wouldn't ever expect over 50% efficiency into the bullet, because you're imparting as much into recoil energy as bullet energy.

 

[Alistair]

Also @DaddyFlip, I would like a copy of your data set to play around with please.

I might break out my old stats module from uni, see if you can do some sort of random forest approach to predict efficiency for new loads and cartridges based on the data.