Load efficiency

[Jimro]

It's a lot easier to just look at the output portion of QuickLoad and see what it says the efficiency is.

You might not choose a .30-06 over a .30-30 but you sure might choose a .308 over a .30-06, exactly because of it's efficiency.

Why burn 55-60gr to get a 150gr bullet to 3,000 when 45-47 will get you to 2900+?

Why burn 56-60gr to get a 180gr up to 2800 when 45-47gr will get you 2650?

Of course, sometimes you just want the speed. The same argument could be made between .223 and .22-250, for example, but I'm happy to take the .22-250.

Brian, you can make the same argument choosing the 30-06 over the 300 Win Mag, and choosing the 300 Win Mag over the 300 RUM.

As case capacity increases relative to bore efficiency goes down in bottlenecked cartridges. I haven't done the analysis on straight wall cartridges to compare cartridge lengths between something like the 458 American, 458 Win Mag, and 458 Lott to see if efficiency decreases as the case gets longer, although I believe it should I can't prove it with any certainty.

Jimro

[Brian Pfleuger]

Certainly true, but I would make the assumption that the question of the effectiveness of the cartridge has already been (honestly) answered.

Truthfully, there's very little that a .300Win Mag will do for the vast majority of shooters that a .308 wouldn't do just as well, or better if you consider shootability and flinch factor.

Sure, maybe you're hunting polar bear, T-Rex or something or you just have to kill that piece of steel from 1500 yards instead of 1000, maybe then you need the uber-magnum.

Most guys, who just want to shoot an elk from 250 yards or a deer from 100, will never need whatever that uber-magnum gives them, especially the recoil part of what it gives them.

In reality, the question of efficiency isn't one we usually ask (directly) but it really should be a consideration, even if minor.

[Jimro]

In reality, the question of efficiency isn't one we usually ask (directly) but it really should be a consideration, even if minor.

And this is from the guy who had to go with a 243AI....

Not to bust your chops in a mean way, I just find it ironic

Jimro

[Brian Pfleuger]

I did say minor.

No, I hear you. I am designing a cartridge that is 100% efficiency minded though.... only uses 28-30gr of powder to push a .243/6mm bullet within about 200fps of a .243Win burning 45+gr.

(I also just ordered a .460XVR)

My .204 and the cartridge I'm designing are like Carbon Off-sets.

[McShooty]

"The question of efficiency isn't one we usually ask," yes, my point exactly when I opined that one would not choose a .30-30 over a .30-06 for general hunting or target work. Examples given where the .30-30 is deemed better for some purpose show the choice is made on the basis of properties other than effiiency. Same for choosing the .308. We like its short action hardware and the ease of finding good handloads, and other things. Efficiency is probably secondary.

For attempts at efficient .243s, and since we have commented on the efficiency of the .30-30, I cite Ackley's 6 mm/.30-30, reported many years ago. However, his powder charges and the velocities obtained do no not differ very much from the .243 Winchester. Nevertheless, Ackley was moved to say "The 6 mm/.30-30 has a case capacity which is almost ideal for the 6 mm bore." (P.O.Ackley, Handbook for Shooters and Reloaders, Vol. I,Plaza Publihing, 1962. p. 296. Granted, Ackley did not have all the fine powders we have now. In the 36, 6 mm/.243 cartridges he lists in this volume, the two smallest cases seem to be the 6 x 47 and something called the ".240 Madame," that is based on a shortened .30 Remington case. Both of these use 30 grains of powder or less. There is a lot of data on 6 x 47 performance in the shooting literature, but hardly any on the .240 "Madame," probably preferred by ladies of the evening. Then there is the 6 BR, well known now, but not to Ackley. Yup, 6 mm, a fertile field.

[Jimro]

Getting back to "efficiency"

If you measuer it at the muzzle it can give you a different result than if you measure it downrange. The more "efficient" a cartridge is at the muzzle, the less "efficient" it will be as distance progresses.

The 358 Win is more "efficient" than the 338 Fed, which is more efficient than the 308 Win. But which one would you choose for a 1000 yard shot? The least efficient option because it has the most efficient bullets as designed for moving through the air.

In 6mm, if you want long slippery bullets, you are looking at the 105 to 115gr bullet weight range. That means you need something "overbore" to launch them at velocities needed for long range.

For short range benchrest, even the 6x45 has done very well. But for a 1000 yard shot, not so much. Although I do want to build a lightweight 6x45 AR with a 20" barrel for deer hunting at close range (200 yards and under). Although that has more to do with the 6mm bore being a state minimum than anything else.

Jimro

[Brian Pfleuger]

Originally Posted by Jimro

If you measure it at the muzzle it can give you a different result than if you measure it downrange. The more "efficient" a cartridge is at the muzzle, the less "efficient" it will be as distance progresses.

I'd have to disagree with that because I think you're mixing two or three different concepts.

The efficiency at which the cartridge converts the potential chemical energy into kinetic energy is over at the muzzle. It has no bearing on what happens at 1000 yards.

If you know you have to shoot something from 1000 yards, the logical choice would be the one that reaches 1000 yards with the best accuracy, least wind drift, etc.

Even so, I don't believe that more drop or drift is a measure of "efficiency". The closest thing to "efficiency" of a bullet in flight is BC and if the two cartridges are firing identical bullets under identical conditions, the "efficiency" difference is not very much.

Technically, the slower cartridge is actually more efficient. A 6mm BR firing a 100gr Berger at 2670fps versus a .243WSSM firing the same bullet at 3100fps... the BR loses 1527fps at 1000 yards while the WSSM loses 1674fps. (42% loss for the BR, 49% loss for the WSSM).

The BR also has almost 24" more drift at 10mph and 12 MOA more elevation but that's not a matter of "efficiency".

[Jimro]

Brian, I think you misunderstand.

The efficiency at which the cartridge converts the potential chemical energy into kinetic energy is over at the muzzle. It has no bearing on what happens at 1000 yards.

Which would be great except that we don't shoot things at the muzzle very often. You can measure energy at any point on the ballistic path, why choose the muzzle if you aren't shooting with your target right against the muzzle? What happens at the muzzle is not what happens several hundreds of yards downrange.

So I think my point stands, you can measure efficiency as energy delivered on target too. The 458 Win Mag pushing a 500gr bullet will have great efficiency and massive muzzle energy. At a 1000 yards that very efficient 458 Win Mag will have less energy remaining, a longer time of flight, than the inefficient 30-06 pushing a 180gr SMK at 2800 fps.

If you know you have to shoot something from 1000 yards, the logical choice would be the one that reaches 1000 yards with the best accuracy, least wind drift, etc.

Which is why I previously compared the 8x57, 30-06, and 6.5x55. As bore diameter decreased efficiency at the muzzle decreased, but efficiency downrange increased in terms of energy deliverd on target, and how quickly the bullets traveled through the air to the target.

Even so, I don't believe that more drop or drift is a measure of "efficiency". The closest thing to "efficiency" of a bullet in flight is BC and if the two cartridges are firing identical bullets under identical conditions, the "efficiency" difference is not very much.

I never said it was. Look at energy remaining at the target distance, look at time of flight.

Technically, the slower cartridge is actually more efficient. A 6mm BR firing a 100gr Berger at 2670fps versus a .243WSSM firing the same bullet at 3100fps... the BR loses 1527fps at 1000 yards while the WSSM loses 1674fps. (42% loss for the BR, 49% loss for the WSSM).

Now you are comparing between different case capacities of the same bore. Back to the 308, 30-06, 300 Win Mag, 300 RUM comparison. We've already covered that, I'm comparing the 6.5x55 which uses 2 more grains of powder to shoot a 140gr bullet at 2650fps than the 8x57 pushing a 200gr bullet at 2500 fps. At the muzzle the Swede is grossly inefficient in comparison, past 1000 yards the Swede has the advantage.

The OP considered the efficiency of the 8x57 and 30-06, so you cannot use the case capacity for same bore comparison, which we have already established as agreed upon definitions.

The BR also has almost 24" more drift at 10mph and 12 MOA more elevation but that's not a matter of "efficiency".

No it is not, and I never said it was.

Jimro

[Brian Pfleuger]

Respectfully, we can't agree whether or not the unicorn is pink if we can't agree what "pink" means. We apparently don't agree on any measure of "efficiency" so I shall leave the discussion to others who's points may not have been made.

[Jimro]

Well efficiency doesn't JUST mean "how much powder does it take to make foot pounds of energy at the muzzle."

I think that we can agree on the concept that comparing efficiency of cartridges is rather meaningless without some idea of range or application.

On the flip side, as "bullet efficiency" is increased with bullet mass and bore diamter, so is recoil.

The 243 Win is a grossly "inefficient" chambering, but having such mild recoil compared to such "efficient" chamberings as the 358 Win is easy to see from a bullet energy standpoint. However if you start calculating the energy of recoil, you could make the inverse argument, that the 243 Win is MORE efficient as less energy is wasted in recoil.

But my point is the same, whatever measure of "efficiency" we talk about, we really have to talk about what is being measured, and where.

Jimro

[Slamfire]

The 30-06 was designed strictly for a bolt action rifle with the early gunpowders of 1900. Length in a manually operated rifle was not that critical but certainly as gunpowder technology improved and full automatic weapons became standard issue, the long case and thin rim of the 30-06 necessitated a replacement. I am of the opinion the Army literally shot itself in the foot when it did not adopt the 276 Pedersen as that round would have been an effective infantry rifle round.

As a hunting rifle the 30-06 is excellent, you can use a large combination of powders/bullets. I shoot more 308 than 30-06 because I am still shooting 308 in competition. For the last couple of years I have only shot 30-06 in Garand matches and I did take the 30-06 across the course last year. Did not do as well as I wanted. The 308 Win is a better round for a military weapon, given that the Army wanted 30-06 performance in a shorter case. I used to shoot 200 grain bullets in the 30-06 at 1000 yards, that extra air space allows more powder and slower burning powders. I tested IMR 4350 in the 308 and never got the velocity I wanted, IMR 4350 works well with virtually all bullets in the 30-06, and I can still use the same powders in the 30-06 that perform well in the 308.

Once you start comparing the 30-06 to magnums, 8mm’s, 375 H&H, then it is sort of “what do you want and what do you expect?”. As a target round, it is obsolete. Actually, the 308 is over the hill as a target round, the 6 mm and 6.5 mm are the way to go, but some matches require 308 Win. The 30-06 is still a fine round, as is, and I am going to keep mine.

[MEATSAW]

Seems like the 7mm-08 or the 338 Federal are really efficient depending on how you look at it.

[griz]

I'll second the request for more info, probably another thread, on the loading info for the 50-Raccoon. First question in that thread - do you install the extension then have it bored and rifled, or is there some magic alignment process?