I had to pick up this magazine when I saw it on the cover titles. The report is done by M.L. McPherson. A very interesting article! I am not challenging his findings, it was of interesting note however when he mentioned that an optimum cased 30 cal. cannot be made. The reason given is no current mainstream action can handle the girth of the case required for the 30-100 SMc.

It was a super idea for an article, but very poorly made.

The silly writer forgot the 9,3x62 (maybe the most efficient cartrigde of them all) but made a big deal out of some obscure wildcats like the 35 whelen Improved and the 7x57 AI!!!? Writing a story just to tell everyone that his particular favorite cartrigdes are the best is not what I consider good journalism.

Talk about messing up a good what might have been one of the most interesting articles of the year.

However, the focus on something else besides speed is always interesting. Makes me regret getting rid of my 9,3...
I think efficient cartrigdes will increase in popularity as a reaction to the ever more overbore new creations coming out that are not really giving hunters more game in the freezer.

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I thought it a very interesting article. In a relatively short magazine article it wasn't possible to give all the details of the research that would be necessary for scientific peer review, but it was nonetheless interesting and I hope further advanced.
It will also be interesting and probably comical to see all the Pseudo-Scientists chime in on how it's all BS because it stepped on one of their personal Sacred-Cow Cartridges or pet unproven theories.
What was presented wasn't confirmed, reviewed scientific fact, but it was leagues ahead of most uninformed opinions spouted forth about internal ballistics.................DJ

It was an interesting explaination of the workings of a heat engine in propelling a bullet.

I still have not made up my mind how useful, if any, it is. Burnng efficiency may or may not be a totally different thing than "usefullness"...depending on the use to which the cartridge concept he describes is put.

In other words, okay, so it burns great...how is it on feeding, magazine capacity, resulting overall rifle weight & balance, and the other sorts of things a person might want in a repeating rifle? If it burns super efficiently and prolongs barrel life as claimed, can it actually be applied to a useful hunting or target shooting tool? Seems to me that is the ultimate test of efficiency for most of us, and I'm not sure of the answer to that one. Have my own ideas, but the article does not attempt to deal with that ultimate test, so I have no hint as to whether my "first opinions" are right on, or completely whacko in that respect.

Hope there are some follow up works by various knowledgeable gun people to further clarify that somewhat muddied issue.

What I got out of the artical was that there isn't a action made thats big enought to handle the 30-100.The artical was very well written

Anytime someone tries to prove shape equals velocity/efficiency a real test shows it is just higher pressures. John Barsness has made a very pertinent post regarding this article on 24HR.

http://www.24hourcampfire.com/ubbthreads/showflat.php/C...9/an/0/page/0#731059

I have not read the article yet, but will get it. Just our of curiosity, what were the specs/dimensions of the 30-100, that makes it unsuitable for current actions?

a .284 cal bullet would need a 505 gibbs action,

a 308 would need even bigger case.

Look here: http://www.superiorballistics.com/information_page/deta...n_on_smc_designs.htm

quote:

Originally posted by Nortman:
a .284 cal bullet would need a 505 gibbs action,

a 308 would need even bigger case.

Look here: http://www.superiorballistics.com/information_page/deta...n_on_smc_designs.htm

While I like the design concepts of the shoulder, I think the CASE SIZE DIMENSIONS is preposterous!!! A .505 Gibbs necked down to the .284 caliber would be WAY OVERBORE even with their propriety shoulder design.

I guess will see how good barrel life is for the 7mm-505 SMC Gibbs in 2007!?!?!?!

And here all this time I thought cartridge efficiency was some way of convinving people to part with their money for the new 3000 wizamabang rather than the 30-06 or 300 Win mag they have in their safe.... Wait a minute, I still feel that way.

Cartridge efficiency is important only to the loaders of the ammo, not the shooter. Lets look at the common claims in favor of the new efficient cartridges. Recoil: recoil is a factor of three things... 1) bullet weight 2) pressure 3) recoil impulse (time that it takes for the energy to transmit to the shoulder). With that being said, efficiency doesn't help with recoil. Accuracy is more a function of the barrel, action alignment and quality of components than cartridge design. Velocity... most cartridges are already excessive in velocity for clean kills out to ranges most of us dare not to shoot at. The modern worry is that the hunting bullet will fragment early rather than expand in the boiler room. (for real fun, launch 150 gr ballistic tips through your 300 win Mag).

Truthfully, I don't envy ammunition manufacturers, after everyone buys a .223, a 30-06, and a 375 H&H, there is not much real need for any thing else. They spend millions of dollars to try to convince people otherwise. Luckily, most of us shooters try not to be rational when at the local gun store and so we do our best to support the ammo manufacturers.

John

Well, efficiency does matter with recoil. Recoil's partly due to the reaction of accelerating the bullet to its muzzle velocity, and partly due to accelerating the smaller mass of powder to the far higher velocity at which the powder gas leaves the bore after the bullet does. Two loads can give identical muzzle velocity, one using a small charge of a fast burning powder, and one with a heavy charge of a slow burning powder. The one with the larger charge of slower burning powder (which is less efficient) will have substantially more recoil than the more efficient load of a smaller charge of fast burning powder. Peak pressure doesn't affect the total recoil impulse, though it may make for a "sharper" feeling kick subjectively as the pressure curve has a higher peak. (Impulse is a term from rocketry meaning the total amount of momentum imparted by the ejection of propellant.)

As far as I'm concerned efficiency is a non issue. For those that think efficiency is important these articles are intersting.....but I can't find any reason at all (including recoil) to own a cartridge that is efficient.....I want one that throws a diameter bullet at a weight at a velocity.....I could care less how much powder it takes.

If I shot thousands of rounds of big game ammo annually this might be an issue.....but for the less than 100 rounds (and often less than 20) rounds I shoot annually this issue is meaningless.

Efficiency is not one dimensional. It's not the pounds of powder you save, or the velocity you can achieve.

We can buy a 30/378 WBY if you want maximum bang.

What makes efficiency important in ballistics is the same reason that efficiency is important in engineering. More efficient systems simply work better.

One example of efficiency are rifle barrel heating. Efficient cartridges burn less powder, and therefore heat the barrel less rapidly. To a prairy dog shooter, this is hugely important. To a competitor under a time constraint, it's hugely important.

Another example is barrel life. An efficient cartridge creates less heat, or can be run at lower pressures, improving barrel life.

For some hunters, these are not of any concern. For shooters, the guys that are trying to not burn up more than two darn expensive Krieger barrels in a competitive season, they are. JMO, Dutch.

I read the article and found it to be 10 pounds of fecees in a 2 lb bag....Just my opinion....

We need it in reality the same way, that the WSMs, and RSAUM offer us something new that we really really need, and don't have already in a bunch of older and more efficient cartridges anyway....

do we all need 4000 fps at the muzzle and 3500 ft/lbs to just go out and take a deer? or boar, or bear, or even an elk or a moose???

I for one, don't think so...YOU want efficient.. try a plain old 250 Savage then.....just another page on the ridiculous to sell more products...

They should spend more money on creating smoother actions, better machining and better fit... at a reasonable cost.. instead of creating new cartridges that one out of a 1,000 really have a need for....

just the way I see it,

cheers
seafire

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quote:

Peak pressure doesn't affect the total recoil impulse, though it may make for a "sharper" feeling kick subjectively as the pressure curve has a higher peak. (Impulse is a term from rocketry meaning the total amount of momentum imparted by the ejection of propellant.)

Huh?!? Impulse is a physics term used to measure force applied over a period of time (measured in Newton Seconds). Then again, I drank a lot when I took college physics. Rifle recoil is measured in force (Newtons)/time (seconds) where F=MA (mass in grams, acceleration in meters/second).

At any rate, powder selection will vary the time factor, pressure will affect the rate of acceleration, and bullet weight will affect the mass. Case design, shoulder angles, or case volume don't come into play.

With that being said, if bullet weight and velocity are equal, the faster burning powder will generate the same pressure in a shorter period of time, hence a faster recoil impulse. I have verified this with a few years of reloading experience and a well calibrated shoulder.

Truthfully, faster burning powders usually have lower velocities at peak pressures than do slower burning powders (verified by Hodgon reloading manual) using the same case capacity. Ideally, there is an ideal for case capacity and powder burn rate vs velocity for a given barrel length, which is what this article addresses; however, with all things mired in the theoretical, having a 3.5" action to throw a .22 bullet is impractical. The egghead types will be impressed that their banana sized 30 cal (where the brass will cost you $4 ea) will be the most efficient; but, most of us are happy to plug on with our inefficient 30-06 where a loaded round cost us less than $.50 in an action that doesn't require a mortgage and can be cycled without having to throw the gun a foot forward while holding on to the bolt.

John

Shooting Times did an artical a few years ago that was similar.

Their most efficients were these:

223 Rem.

7X57

308 Win

They also had the most efficient belted magnum, but I don't remember which it was.

The fact that they nearly all were military cartridges was credited to the vast research done to provide the most "bang for the buck" in times of war.

Did y'all notice HERE that the ACKLEY design---with its 40 degrees, though the picture shows 45 degrees---is just about as good?!?

Woods,

Yup. That did cross my mind. So does the 22BR. However, the one thing those two do not always have is the long neck. The older I get, the more I like long necks (and that's not just the influence of my stint in Texas talking).

The one thing that piqued my interest especially, is the admonition to keep powder densitiy at 95% or above to prevent pressure spikes.

Why can't we have efficiency and uniformity at the same time? FWIW, Dutch.

quote:

Originally posted by Big Bore Boar Hunter:
Huh?!? Impulse is a physics term used to measure force applied over a period of time (measured in Newton Seconds). Then again, I drank a lot when I took college physics. Rifle recoil is measured in force (Newtons)/time (seconds) where F=MA (mass in grams, acceleration in meters/second).

Yes. That's what impulse is, as I said. Rifle recoil is normally measured in terms of "free recoil energy," which is a function of impulse and the weight of the gun being tested. Measuring in terms of instantaneous force is problematic in a number of ways. It becomes relatively meaningless when there's anything but a perfectly rigid connection between the breech of the gun and your shoulder. I acknowledged above that you may feel a sharper sensation from a short recoil force curve with a higher peak thrust, but you may not, depending on things like whether the gun has a flexible Tupperware stock, a recoil pad, what sort of clothes you're wearing, how snugly you hold the butt against your shoulder, etc. The impulse, a good definition of which you gave above, is a more constant figure for comparison. And it is greater with a larger powder charge for the same bullet velocity. (Lower efficiency.)

I read it... then wondered why anyone would care?

AllanD