In the March/April edition of Peterson's "RifleShooter" Magazine there was an interesting article written about the effects of case design and how it affected effeciency, powder burning characteristics and recoil.

It seemed, at first, like a really well thought out, examination of the topic. Later in the article, it is revealed that the author - M.L. McPherson (a so-called "Guest Columnist") is actually a co-partner with another man, in a company "Superior Ballistics Incorporated" - and that they have actually patented and protected the ideas on case shape - that the author wrote about in this article.

Seeing that, changed my own reading of that article. Instead of being really fascinated as I was, by what I thought was a new and objective look at how the case shape of a cartridge might affect it's performance characteristics - I now found that I was reading the article very skeptically, thinking that all I was now reading was merely a 3 page "info-mercial" - in what looked like an "article".

I think allowing a partner in a business venture to get three pages of free advertising under the moniker of "Guest Columnist" in article form is in extremely poor taste and poor judgement from a business/ethical standpoint. Personally, if I were the editor of such a magazine - I would have asked for the authors to turn over their data and a sample gun and rounds over, and had one of my own trusted writers check the claims - and write about what they found when they checked the designers claims. This, to me - would have been how to run a magazine. But what do I know? I'm not an editor.

Having said that, the information that was provided - is not automatically false because of this - just now "suspect" from my own sceptical point of view.

To sum up the article - it says that case design (if done in the way they have patented) can provide huge benefits in cartridge effeciency. Namely that their cartridge - the 30-100SMc can generate 10 % more velocity than the .300 Weatherby Magnum - with essentially the same pressures and that the 30-100 SMc can duplicate .30-378 Weatherby performance - despite having 33% less usable case capacity.

I find these statements amazing - and if true - exciting. But as I said - because the author stands to benefit financially from these claims - I can't help but wonder about the veracity of these claims.

What do the rest of you think about these claims - and the way in which they were allowed to be written?

I'm sure I'm in for some interesting opinions...

I find "cartridge efficiency" one of those minutia-management topics for the anally-inclined...

I read the article, and I share some of your scepticism. That said, McPherson has been writing a series of articles on the same subject, in magazines such as Varmint Hunter Magazines.

In that light, this article was sort of a cap-stone on his investigation of the subject.

I've played with different cartridge shape and efficiency long enough now to know that there IS a difference.

What I don't buy is the "cooling" plug, and the long neck/throat erosion argument. Not the part where the long neck protects the neck -- that I buy. Just not the logic behind it.

All in all, I'm enough of a "thrill seeker" to rebarrel one of my Savages to a 5.0 SMc, or whatever. Sounds fun to shoot. JMO, Dutch.

Brad - hate to differ - a 33% gain is huge! "Minutia" - is when we argue about cartridges being "better" or "deadlier" because they shoot a bullet out 100 to 300 fps faster - (less than a 10% faster for most modern magnums) over standard calibers.

I think BCBRIAN's point was as much about the sloppy editorial policies of Rifleswhooter" magazine as they were about cartridge efficiency.

For me, case shape is only important when deciding as to whether or not I wish to acquire it. It is a visual consideration. I think of it in the same way as I think of the female form. It must be pleasing to the eye.

Efficiency doesn't enter into the equation.

Did the article give any data from Norma? McPherson was to commission them to do a blind test on some design of his. The article I read was from Precision Shooting a year or two ago.

His cartridge has a convex shape to the shoulder.

I don't have any problem at all with a magazine accepting articles from people who have a vested interest in the products they are talking about. If we didn't have people doing that, there would be far fewer articles written.

What is important is for the writer to be transparent about his position, and to use correct data and analysis to support his claims and conclusions, so they will bear examination. This hobby is awash with myths and legends that started without data, and continue in spite of it.

Steve,
I do the same thing. So which ones catch your eye? I still like the 270 WCF, especially with 150gr Partitions seated out about as far as I can get them. Mean! <img src="/ubbthreads/images/graemlins/cool.gif" alt="" />

I also think the K-Hornet looks pretty good.

- stu

I appreciate beauty too and I like efficiency as well. I do not see any reason to oppose them.

An efficient shape can be a beautiful one.

Stepping over a dollar for the sake of picking up a dime isn't a game that I care to play, and the concept of "efficiency" can be very misleading and oftens provides a very narrow margin of return and a false sense of economy. And quite often, there's no practical economy realized whatsoever.

For example, it doesn't matter to me if the 35 Whelen Improved is actually more efficient according to the parameters of that article than the 338 Win. Mag. The 338 Win., in terms of ammunition and brass availability, is pretty much a standard world cartridge that outperforms the 35 anyway, and I've been into camps even in some of the most remote parts of Africa in which the safari company kept some 338 Winchester ammo in stock.

There's nothing "efficient" about fire-forming brass, nor is there anything "efficient" about hunting on the other side of the world, with the only possible source of additional ammunition being on your loading bench back home -- some 10,000 miles away.

Sometimes "efficiency" can become a very bitter bargain indeed...........

AD

I bought the magazine but haven't read the article yet.. I am really interested in case shapes and design and want to know all Ican about them. it seems the shorter cases are a bit easier to get accurcy from inquiring minds want to know why. <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

Reminds me of the old Herters design with a double shoulder that was supposed to give higher velocity with lower pressure using "swirl" method of burning powder.....

Sure enough, one must know when to stop the quest for "better still" ...
But the quest is legitimate.

If this quest had not taken place we would still be throwing rocks.

These articles are a pet hate of mine.

I appreciate a .308 over a .300/378 because it is more comfortable to shoot and does the same job over usual hunting distances, but, I would never disguise the truth under the banner of efficiency.

I have a .30/06 and also a .300 RUM. The rifles are blued/wood in the former and stainless/synthetic in the later.

The .30/06 is a sweetheart to carry and use, the .300 is "bang for the buck" if I create a need for it in my own mind when hunting in foul weather.

Inventing a need is another way of providing justification, we all do it, why not call it straight?

AGW

.22 LR just maybe the most efficient round of all times

Brian--

There are two kinds of "efficiency" being discussed about here:

1) The kind of efficiency that results when a smaller case is used in a certain caliber. This is one of the basic laws of ballistics. A .308 WCF is more efficient (50 grain capacity) than a .300 Rem. UM (100 grains capacity) because it turns more of the powder's energy into bullet energy.

In the .308's case, 50 grains of powder is turned into 2700 foot-pounds of muzzle energy, or about 54 foot-pounds per grain of powder. In the .300 RUM, 100 grains of powder is turned into about 4200 foot-pounds of muzzle energy, or about 42 foot-pounds per grain of powder.

This is also why the .22 LR was mentioned as the most efficient cartridge ever. It turns about 1.5 grains of powder into 150 foot-pounds of muzzle energy, or about 100 foot-pounds per grain of powder.

In general this ballistics rule is simple: The less powder capacity for a certain bore size, the more efficiently the case turns powder into muzzle energy.

2) The second kind of "efficiency" breaks this rule. It has been searched for by inventors of cartridges for over a century now, usually with trick case shapes.

Here, case shape is supposed to help powder burn more "efficiently," producing MORE muzzle energy per grain of powder than can be done in a case of conventional design--and the same powder capacity.

The list of cases that have laid claim to this is long, including Roy Weatherby's "double venturi" shoulder cases, and the short-fat magnums. John Lazzeroni has long claimed that the case shape of his short-fat magnums allows them to reach unheard of muzzle velocities for such case capacities.

Trouble is, every time somebody pressure-tests such rounds, the factory ammo is loaded HOT (as is the case with Lazzeroni rounds, and early Weatherby ammo). If the cartridge is loaded to more conventional pressures, it ends up using the same amounts of powder to produce the same amount of foot-pounds as a conventional case of the same capacity.

A prime example would be the .280 Remington Ackley Improved and the 7mm SAUM. These have capacities within a grain of each other, and produce exactly the same ballistics when loaded to the same pressures. Case shape has nothing to do with any sort of improved efficiency in the short-fat.

I have a little more insight into Mic McPherson's round. I was recently invited to test a rifle chambered for a similar round that Mic and his partner had invented, but in a different bore diameter.

I took them up on it, but had to abandon the project about halfway through because I found that, due to "deep background politics," I couldn't publish my results. This round was supposed to produce its unheard of ballistics through a combination of case diameter and a slightly curved shoulder--so slightly curved that it could barely be detected by the named eye.

But I did fool around with the new cartridge enough that I am skeptical of the claims of its inventors. I measured the case capacity and compared it to a coventional cartridge of the same bore size, for which pressure-tested data is abundant. I calculated that the muzzle velocity claims for the new wildcat were just what they should be for a case of such capacity, no more and no less.

I also found that the fired brass sent to me for the project had primer pockets so loose that some cases would not hold primers.

I never did get to pressure-test the round, but from my little acqaintance with it doubt that it breaks any ballistic rules.

MD

Friend John,


As always, you are absolutely correct. There is no magic cartridge and, as far as I've been able to discern, case shape has absolutely no bearing on muzzle velocity. Capacity IS velocity... Period.

I love your comment about "deep background politics." Don't you just hate it when that kind of crap pops up? You want to help the folks. After all, that is the reason that you and I write. And yet sometimes it is impossible because of political or advertising influences. I hate that part of writing.

Steve

There goes Mule Deer again, throwing water on the fire.

We need Big Stick to chime in and throw a little gasoline on the fire. . . . . . (grin).

That's much more fun.

BMT

Thanks Gentlemen, for confirming what I strongly suspected.

When loaded to equal pressures - bigger cases shoot bullets out of barrels faster - but with a negative logarithmic curve concerning how much extra powder it will take - to speed up bullets very much. Meaning, it takes a lot more powder, producing a lot more muzzle blast, a lot more barrel wear, and a lot more recoil, to speed up a bullet - just a little bit.

Cartridge shape (in my own experience) seems irrelevant - except perhaps for benchrest - where short squatty cases have ignition characteristics that do seem to improve accuracy - but to such a slight extent, that no hunting rifle would ever show it.

Sad thing about the "politics" thing you mentioned - I feel your pain. You want to tell it like it is for your readership, but you end up getting over-ruled because to do so could hurt advertising revenue.

Sad - but true. Some day I hope a magazine editor will instruct his writer's to "tell it like it is" and then let the chips fall where they may. If that ever happens - that magazine will have my undying loyalty. Until then - I understand.

I'm with Brad on this one. My take on cartridge selection ....

concerns regarding the efficiency of a hunting cartridge (ie case volume vs bbl length) are basically pointless.

#1 choose your bullet diameter and weight

#2 choose the velocity you want said bullet to move at

#3 choose the barrel length you are willing to carry

#4 choose the cartridge which will give you #2, given #1 and #3

You will find an ample selection of cartridge size/design that will fill just about every permutation of #1,#2 and #3, and when in doubt, default to the next biggest common factory cartridge

When the Precision Shooting article came out by McPherson I called an engineer who is a shooter. I was told that the energy produced would be the same if the only change was the case shape.

This is why I asked if McPherson had published any findings from Norma as he said, at the time of the article, that he was having Norma do a test?

On the other hand this is the fun of cartridge selection. And it's not without relevance. Some hunt regular game at woods ranges and there a magnum is indeed a waste of energy with negative paybacks in terms of gun weight, shot placement, recoil, muzzle blast and even meat damage. Then at long range even the giant magnums don't shoot nearly as far as I can see.

Then there are all the myths of cartridges layered over this as mentioned earlier. The bottom line is that its fun to talk about and once in a while a reality check such as this topic is good.

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? Even if 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.

Government size is, by its inherent nature, inversely proportionate to the freedom of its citizens.

JB is on the money here in my experience (ballistically and politically).
The one thing about cartridge shape I would point out, however, is that in longer powder columns, the powder toward the base of the bullet gets pre-heated by the powder burning behind it, effectively increasing its relative quickness.
In the short-fats, you don't have as much pre-heating, which is why you generally see them loaded using faster powders.
From my own testing I've basically stated that "efficiency" is so easily skewed up or down by handloading that it should only be of importance to non-handloaders. And that for them, the whole efficiency thing is purely acedemic and a good campfire chat topic.

Savage99, good post, and I will change my position to state that in a hunting context efficiency is irrelevant IMO.

I read the article in RifleShooter, and thought that the claim by McPherson had some interesting parallels with the front ignition - duplex loading work by Elmer Keith and friends just before and during WWII. That group made some extraordinary claims, but would not publish the exact details because of patents pending and other unclear problems. The exact mechanics of what Keith's group had done did not come out for about five years after the first article appeared with its claims of cooler burning and higher velocities.

As I recall, Keith's claims had some validity - front ignition was more efficient, in terms of getting more velocity from the same amount of powder, but getting that velocity was way more trouble than it was worth. Julian Hatcher noted that the military had been using front ignition for decades; it was worthwhile in artillery shells, but the principle was not new.

Front ignition techniques, in which the primer flash is fed through a tube to the front of the powder charge, effectively alters case shape from the usual rear ignition.

It will be interesting to see whether this claim plays out similarly.
--Bob

Brian--

Yeah, cartridge shape does have an effect on accuracy to a certain extent. In general, shorter cartridges seem to burn powder more consistently from shot to shot, but this is not efficiency.

Cartrideg efficiency (in the first sense I listed above) only affects hunting cartridges in that more efficicent cartridges recoil less for the amount of work they do. This definitely has its effect on that nebulous thing called "shootability."

The "deep background politics" of my not being able to write about the new round had nothing to do with advertising revenue. It had to do with a clash of personalities, which is not exactly uncommon in the shooting biz.

MD

The front ignition is fact, but it has nothing to do with cartridge shape.
It was validated by Keith, O'Neil and Hopkins with the OKH cartridges, Hatcher with artillery, Davis with the 7 mm Rem. Mag and most recently with Knight and the "power stem" breech plug.
How it works is that powder has mass, and it doesn't all burn at once when the primer goes off. Yes it burns quickly, but not all at once so some unburned has to be pushed down the barrel along with the bullet until it is fully consumed. By igniting the charge at the front, less energy is expended on pushing the gas and unburned powder, so that energy is instead used pushing the bullet. The increase in velocity is modest, but statistically it's there. When you consider an average powder charge is around 50 grains, that's a lot to push. It's like the difference between shooting a 150-grain bullet and a 200 grain bullet in a .308 Win.

When I am down to my last can of powder and there is no more to be had----that's when I will start worrying about efficiency in terms of fp/grains of powder and how many cartridges I can load with a pound of powder. If you have to worry about that, you can't afford a license or gas to drive to the hunt anyway. And you should probably sell your rifles anyway to buy shoes for the kids <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> They do take to whining in the wintertime about going barefoot.

Kind of like listening to a guy in a $3,000 duck boat, shooting a Benelli, with a thousand dollar dog and a huge duck lease....bitching and moaning about what he paid for shells. Tunnel vision, I think its called.

we're in agreement.

Mule Deer----just for clarification please.
So if you load the 280 Rem AI and the 7mm SAUM with the same amount of a like powder, they develop the same pressure and velocity, all other things being equal????? There is no difference in the pressure curve either????
This being the case then the tendency for shorter rounds to be more accurate is only due to the length/stiffness of the action or????

"Loading to the same pressure" is not the same as loading the same components in the same quantity. If the cases have similar capacity, but different shapes then to rate the "efficiency" of the cases, you should use the same load specs and check comparative performance. If you achieve the same pressures but with different powders, you are not accurately checking the "efficiency" of the two cases (the variable). The proper check of comparative case shape efficiency would have all the variables the same except for the case shape----------no lets not go off the deep end with design of experiments, etc.
Would different pressure curves change the harmonics and could that have something to do with the perceived accuracy improvements with shorter and/or fatter cases?

The real answer to "Why case shape matters" is that some of them are "cool" such as the 284 Win. I rest my case.

The 7mm SAUM and .280 Ackley don't have exactly the same case capacity. The SAUM holds a tiny bit more, just how much depending on how heavy the individual brand of brass. But in general, yeah, you have the idea.

The accuracy edge of the short mags has been attributed to a lot of things. The biggest factor, probably, is the short case. This promotes more consistent burning of the powder from round to round, primarily because the primer flame reaches more of the powder column.

The short action is also slightly stiffer, just how much depending on the action itself.

All of this is really picking nits, however. If you have a well-built rifle with a good barrel, I sincerely doubt the average shooter will be able to tell any difference in accuracy.

Accuracy has nothing to do with efficiency, however.

MD

There are several that I think are attractive to look at.

The 7.62x54R, a sexy Czarist tease, reminiscent of the daze when discussions about cartridge efficiency leaned more toward killing power than horsepower.

The 22 Hornet, because it's so ugly, it's cute. Much like your little brother. The little guy you let hang around because you felt sorry for him, but never showed your love publicly.

The 222 Rem, because it forced the issue of accuracy in the modern target era, spawned the 223 and made the PPCs. Yes, it inspired cartridge designers who "took aim" at it, in order to beat it.

The 45/70 with a big, honkin' blunt bullet balanced on the end. What else does one need to say? It's like the bumble bee. It shouldn't do what it does, but still does what it does. Doesn't it?

Finally, the 375 H&H. They've been trying for years to duplicate it, but haven't got it quite right. You can launch a comparable bullet at the same velocity or faster, but everything that came after lacks the charm of the original.

Accuracy's efficiency is normally measured by game harvested and match scores. Just had to pick one last nit (just for the fun of it).
I realize the largest variable of all is the nut behind the gun.
You are correct that most of us are not consistent enough to tell the difference in a well built gun, and in the average gun----well lets just go shootin and be happy we can.

It's funny how beauty, is indeed in the eye of the beholder.

Personally, I find long, gradually sloping (or non-sloping) rounds like the 375 and 300 H&H and almost all the straight sided lever-action cartridges just plain ugly.

To me, the good looking rounds are the one's that are short and with a square set of shoulders on them. Sloping shoulders are as ugly on cartridges as they are on people. I like cartridges designed to function under real pressure.

To me, the best looking cartridge would have to be the WSSM's - with the 25 WSSM being the most beautiful.

But then, I think most professional women models are unattractive - go figure eh?

Most of the WSM cartridges will go the way of the dinosaur I suspect. What is it that they say? Only the great stand the test of time. But it is okay to admire their form. Their outline is unique.

Winchester put too much faith in a cartridge line at the expense of the others and has been sent to the corner for a time out. They are being punished by the devil gods of Bedlam. St Barbara weeps.

Just remember what happened to those that worshipped graven images and golden idols!

John,
Not denying the validity of your statement at all but simply adding to it: I submit that it's almost impossible to compare the accuracy of two different cartridges using two different rifles because of the inherent accuracy of two different barrels. In benchrest the shooters are driven to the ragged edge of sanity by chambering as many as 20 barrels from the same maker and only finding 2-3 that produce the accuracy level necessary to win the Super Shoot. Nobody knows why but this is a demonstrable fact. Sad to say that I could never shoot at the level necessary to really determine the great barrels..... <img src="/ubbthreads/images/graemlins/blush.gif" alt="" />

Steve,
I've said the same thing many times. The short magnums probably won't last long in popularity. There will always be a few who want one but not enough to sustain any 'energy' of a rifle compnay.

------------------------------------------------------------
Just remember what happened to those that worshipped graven images and golden idols!

-----------------------------------------------------------

We still have plenty of those. Always have and always will.

Jeff Cooper said it well: Superior minds are concerned with ideas, average minds are concerned with events and inferior minds are concerned with personalities.

I made the statement to a yankee acquaintance once that slavery is still alive and well in the US of A but it's the Federal Government that owns them now.

You would have loved my first wife.....she was short and squatty, too! <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

One thing that helps the short mags as far as accuracy goes, is the extremely short throats they have. Most common cartridges have overly long throats on factory barrels. Probably a quest for liability concerns from the bean counters...

Simply put- If you take a 300 WinMag and a 300 WSM and have them chambered by a good gunsmith, the accuracy would likely be the same. The Winnie would be a little faster given equal barrel lengths but not by a huge margin. As was stated earlier, the standards are much easier to deal with as far as finding Factory ammo in a pinch.

I think the 300 WSM has a good chance of making it in the long run but the other short mags will likely fall by the way side. After all, this is 30 caliber country...

Mickey is exactly right. He also knows how to put a rifle together to SHOOT. I have shot some of 'em!

Winchester hit the jackpot with the .300 WSM. At one point shortly after its introduction they were selling 700% more than they projected! I believe it will be a standard cartridge for a long, long time.

The rest are iffy. The second-best-selling WSM is the .270, but it is way behind the .300. The 7mm never really got out of the gate due to taking too long to be finalized. The WSSM's are dead in the water.

I have heard conflicting reports about the .325. Here in the West it hasn't sold well, but I have heard the Southeast boys like it. Must be deadly on those 100-pound doe whitetails and barbecue pigs. I never could understand what it was supposed to do that any .300 magnum wouldn't, but then I often get in trouble by asking too many questions.

MD

But one cartridge does not a business make. Really, it should not break one either. It's not as simple as chambering too many rifles in their WSM/WSSM line, but when you're on the ropes, if you gamble, you must accept the result. That idea didn't help things.

Is it fair to say that chambering and marketing the WSM line of cartridges in their rifles was worth the result? Time will tell. Personally, I don't think so. Whether you like short and fat or long and skinny (sounds a tad kinky) the writers of tomorrow will have a field day reviewing the events that we are living through.

I expect that their future conclusion will be "obvious" for all to see. Why couldn't the company see it that way back then?

I don't think I'm bright enough to understand what all of the fussing and fuming is really all about as it applies to case shape and configuration, short versus long, the significance of powder efficiency ratios, etc. From my ignorant point of view, a lot of it seems to be an exercise in mental gymnastics, and I think a lot of guys are more pre-occupied with pole-vaulting over mouse turds, theorizing, collecting a safe full of rifles that all do pretty much the same thing, and punching paper than they are hunting.

Case in point, for the last 12 years I've used the 300 Win. Mag. more than any other cartridge in a score of states and eight foreign countries, and on a great many big game animals of all sizes, up to 2,000 lbs. in weight, and at ranges up to just over 500 yds. Yet, if you listen to a lot of the chatter, the short neck, belt, case length, powder efficiency ratio, etc., all make the 300 Win. Mag. some sort of a dinosauer that's not supposed to work just quite right.

Even so, I've never had a feeding problem, an accuracy problem, or a reloading problem with this cartridge. Nor have I been alarmed with or have given a rusty about recoil or if maybe its powder consumtion ratio isn't quite optimum. However, despite all of those purported drawbacks and potential hassles that haven't yet seemed to have manifest themselves or gotten in the way of terminal performance, it's just-plain worked for me anyway -- that's all I know.

Maybe I've been doing something wrong and and have been plagued with problems after all, and I'm just too dumb to know it!

AD

.....and here I was scrolling through and reading this thread with my own response about how all is naught if it doesn't go through the gun right come hell or high water...........and there just is nothing like one of those sleek H&Hs to do that, never mind all the theoretical advantages to the likes of the new beltless stuff and so on. And at that point, who actually gives a rip if it requires more or less powder to "get there." I won't even touch the accuracy thing since both the 300 as well as the 375 have an accuracy track record of some repute. Any difference for their normally used purposes is pretty much nil.

(And though I differ on cartridges- not so much because of appearance- I do have to agree with you on the human shoulders thing. I can't imagine us shaping ourselves as was considered attractive 200 years ago with corsets, etc to get a certain long-necked look....not sure that some of the presently popular human sculpting is any better though.........)

Unfortunately, living overseas at the moment, I can't get my hands on that article. The short fat cases do have a slight advantage in general. For a fixed barrel length, they get a bit longer bullet run. That means a greater expansion ratio, and that is well proven to up your efficiency. As others have pointed out, though, higher pressure increases efficiency as well, and I wouldn't be surprised if this old trick is being used to improve their efficiency claims. That 10% increase in fps means 20% more efficiency, which sounds pretty iffy. In my copy of Cartridges of the World, there is a picture of one of McPherson's cartridge. It sure looks to me it will enjoy some of the advantages of frontal ignition, the case body being shorter than it is wide. Still, I'm not convinced there's quite that much to pick up from the effect, though.

It is no doubt equal pressure will do only an equal amount of work. That is a given.

Can case design give more pressure with less powder? That is Cartridge Efficiency.

As far as the elliptical sholders go, once the powder has burn down to expose the sholders the show is all but over. If the powder is in an elliptical shape it would be a differant story.

All this talk about catridge efficiency - hell boys just fill it up! <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

Yea. Just give me a bullet with a BC around .440. Moving around 2680-3000 fps and I'm happy. Oh yea, Less then MOA too.

I know I'm jumping in kinda late on this one, but here's one that always burned me up. Have you ever been to Fred Z's Z-Hat website. In the old days, he had this write up on how the Z-Hat cartridge were so "efficient" and had some total BS explanation for it. I see he has updated this explanation to make it more plausable, but I still don't buy it.

http://www.z-hat.com/Efficiency%20of%20the%20300%20Hawk.htm

This particular graph I find ludicrous:



You really think there is something "magic" about blowing out the '06 case to hold maybe 8% more powder and all of a sudden it becomes more efficient than the '06 AND the .308 Win. C'mon Fred, get real!!! What he's really doing is comparing selected reloading manual velocities with his amped up handloaded velocities.

MM

Damn. All this and not a single mention of the "point of
dimishiing returns"? <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

I notice the article you linked emphasizes "kinetic energy" as a comparison point. Since the kinetic energy calculation uses the square of the velocity, any difference in velocity causes an amplified difference in kinetic energy. Plus, like MuskegMan said, the comparison uses average velocities and is not a true apples-to-apples comparison with factors like pressure, energy content of the powders used, etc. controlled. There was, obviously, no controlled experiment run. Junk science.

As I read this I can't help wonder, if having the same case pressure to achieve a certain velocity is such a big deal, why do we bother with bottle neck cartridges? Then what was so bad about the cases like the .375HH, .30WCF and the .22Hornet.

The only thing is,the .30-30 could achieve higher pressures then what came before it. The .300savage had higher pressure then the .30-30.

As modern metallurgy improves and modern gun power improves, pressures go up. It's a fact. Face it. Move on.

Loaded to the same presures, black power will do the same job as modern gun powders. At least that is what I see in this topic. Or am I wrong?

So I say; if case shape didn't matter, all cartridges would have straight shoulders. Or, no two would look alike.

If the firearm can take that pressure, use that pressure. That is were pressure is most important.

Until there is a viable and reputable study done where the case capacity is constant, but the shape is changed and all other variables held constant, I will hang on to my belief that the .284 Win case will match the 280 Rem and use a couple less grains of the same powder to do it.
I am talking about using the same barrel, etc. ie: all things constant except the case shape.
Yes I know the 284 has slightly less capacity than the 280, but it is my belief that if the capacity was identical the shape of the 284 would cause it to out perform the 280 (higher velocity)-----ie truly be more efficient with all the variables held constant.
I have to believe that if you vary the powders used, but load to achieve the same pressure, the velocity will show some variation depending on the shapes of the different pressure curves
Just my $.02 worth. but some would say I am not up to that value.
mrk

Gentlemen, efficiency is primarily a function of the pressure limit and the expansion ratio.

Neither alone is the figure of merit. A .300 Wea in a 6 inch barrel is far less efficient than a .30-30 carbine. A .44-40 rifle is less efficient than a .44 Mag revolver.

It's the ratio of KE to charge weight that is the measure of efficiency (more or less -- some powders carry more energy per grain). Whether you care if you're burning a little extra powder is another matter.

You talking to me? <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

I think many are missing the point of the article. The "plug" of powder not reached by the initial primer blast follows the bullet unburned and the elliptical shoulders cause an epiphany to be as yet understood, although the author tackled it as best as he could for laymen. It has been proven with sub 30 and now will have to wait until someone builds the 30 caliber model. That may not happen because it is so unconventional. Does that sound familiar? Think out of the box. Maybe progress has been waiting for 100 years but we missed it.
For hundreds of years, it never dawned on scientists that a different shape other than round ball might result in better ballistics downrange.

I suspect this cartridge epiphany is along the lines of "cold fusion." In the end, any gains in efficiency will be found to have been experimental error.

I had QuickLoad pretend the gases didn't accelerate at all, they just magically push the bullet without having to accelerate themselves. I also shortened the case to pick a little extra expansion ratio. Even in this land of make-belive, efficiency was raised only 14%, less than claimed on their web site.

In looking over the web site and the US patent, I don't see any experimental evidence backing up their claim. The tests at Norma didn't even use the same primer in the two cases compared!

To be sure, coating the cases and bullet with heat insulating material must up efficiency some. The mysterious focusing of the primer shock is certainly an interesting theory, but where's the data backing it all up? Some of their claims for efficiency are based on an assumption of powder burning I don't believe has been demonstrated.

As always, the proof will be in the pudding, and that doesn't appear to even have been cooked yet.

Personally, I don't care it Z-Hat's cartridges are technically the most efficient rounds on Planet Earth, and live up to the claims of their originator. There's more to cartridge selection than all that nickle & dime stuff.

The one thing I know is, Z-Hat's cartridges present some real logistical problems that, in a very real way, make them inefficient by default.

Not for me..........

AD

AD, How right your are! My buddy has had a set of dies on order from Zeglin for over a year now, and still hasn't even been promised a delivery time. Maybe there are some issues involved.....................DJ

What article? <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

I didn't post any article? <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

All righty then.

The shouders would, will and do hold more of the unburned powder from being pushed up the barrel. In doing so it exposes more powder to the flash (according to page 23).

Which one will hold back a more predictable and consistent amount of powder? A short fat case or a long thin case.

It looks to me as though a long thin case would exposes a greater surface area to the flash in a shorter amount of time once the "plug" moves but with the same percentage of deviation in plug size the short fat cartridge would be more consistent in the amount of powder being exposed once the "plug" moves.

This would mean that the case would have to be proportioned to each cal. Such as the .30-06 to the .50BMG. No famly of cartridges like .308, 7mm-08 and .243.

What would a .30 cal. look like if it had the proporition of the .243WSSM???? What would the action look like? Could the old school deal with it?

If a new cartridge design is to be more efficient at converting powder energy to bullet kinetic energy, then it has to reduce one or more of the known causes of energy loss:

1. When the bullet leaves the muzzle, the propellant gas vents into the air. Compressed gas has potential energy, so venting it is a loss of energy. In the case I have calculated, it carries away more energy than the bullet. (Relates to 2525's statements about peak pressure and expansion ratio.)

2. Friction robs energy. It's not much, roughly 300 foot pounds.

3. Hot gasses are in contact with steel, and the steel absorbs heat. This is a big source of energy loss... probably about 1,500-2,000 foot pounds.

4. Rifle recoil carries away about 25 foot pounds.

So my question is, which of these is affected by cartridge shape? So far, I can't see where it has any effect on any of the known energy losses.

Mark me as deeply skeptical on that one.

OTH, I have handled a rifle with the new chambering, and the explanation I got of its benefit was quite different. The curved shoulder acts a focusing device, like a telescope mirror, to focus energy from the primer "bang" on a point near the front of the cartridge, giving "dual ignition" and better burn consistency. Now that sounds plausible.

Are we looking for "known causes of enery loss" or ways to be more efficient in energy generation/conversion?

280don

The March/April 2006 of Rifle Shooter magazine has an article by M. L. McPherson alleging case shape matters. It is 3 pages long with several diagrams, internal and external, explaining the position.

Do you think the curved shoulder acts as a focusing device once all the powder has burned to expose the curved shoulder? I know that the artical shows this.

I think the Vee or cone shape of the unburned powder behind the shoulder would have this effect.

I'm not a good person to take on this one. My pet deer rifle is an A-Bolt S/S in .25WSSM with a 120gr bullet. The rifle just feels right in my hands. What I think is more important is staying away from sound barriers. I can live with less then MOA and some flattend primers.

I also like the .22Hornet. It's in my speed zone. The .22Hornet case shape and shoulders couldn't be more different then those of the .25WSSM. My CZ 527 and A-Bolt are the same size! So you can see what is important to me.

Anybody remember who the "experts" were who were shooting for the 5000Fps mark. Last I heard from several years ago, they had given up due to impractical barrel length, and unforeseen problems with projectiles and other components.

Think they were involved with some kind of military research, but were also looking for a "zero gravity/friction/hyper" varmint round with possible commercial applications.

I think they did have some success with the high 4000fps.

Front venturi burn effect is not new. Method to achieve might be. Elmer Keith and two partners formed a rifle company some time back and went broke. From what I read there was some merit to what they were trying to do, and also a awful lot of pro and con debate over their idea.

They called their rifles and cartridges OKH (K for Keith), and don't remember the names of the other guys. I think Bob Hagel used some of these rifles quite a bit until the split.

Doggone it MColeman! If your quote from Jeff Cooper is accurate, I just found out I've got an inferior mind.

However will admit: A good idea is interesting, and I did buy a 17M2 because the cartridges were too cute to resist. And, I do think eventually we will probably see the M2 go the way of the 5mm rimfire.

Anything there redeem me somewhat?

P.S. I keep waiting to see some guy walking down the street in the city wearing the M2 as earrings. AND, IT AIN'T GOING TO BE ME!

O'Neil and Hopkins were the other two.

Deersmeller,

Thank you sir!

I have Elmer Keith's old .285OKH Mauser, the rifle on which he did the front ignition flash tube development and which is photoed in his books, plus 18 of his loads with flash tube, 55 grains of 4350 and the 180 grain WTCW bullet. Some year if I live long enough I will shoot some over a chronograph (which if EK did he never wrote about in print) and we will see how fast it is.

Come up to CT! I have a Oehler with a 4' three trap bar and it gives reliable readings.

PM me and we can get together any nice day. The range is just off of I-84 east of Waterbury. It can't take more than 90 minutes from the city.

[color:"red"] [/color] I would like to suggest an internet search for the name of M. L. McPherson. I knew the name, but my ole' mind could not place it. [color:"red"] [/color] I did and he has written for many years. Check your copy of Cartridges of the World. He and and Frank Barnes edited it. Mr. McPherson is well known and respected in the gunwriting community.

What he writes about in articles and books is well researched. Sometimes it gets a bit deep and is technical. However, I for one have read numerous of his pieces and have found no fault with his opinion.

I do believe I am correct, although not positive, it was McPherson's idea behind what we now know as "short Magnums."

Do not sell him short.

I think the reason the .30 hasn't been made is the bolt face diameter is to large and it would require a whole new action. 1 in the chamber and one in the magazine. This could be a problem.

No, sorry 280don. I was replying to MuskegMan's post, but just typed it in the quick reply box...

Should you ever get around to shooting and checking out your OKH, post your findings here for us if you will.

Will see what I can find in my library on them, though those books and articles have a tendency to "disappear" from my possession.

The best my memory serves me (about a 2 on a 1 to 10 scale): they did have some success with it in the field, it seems to me they had a problem with the venturi "burning out"; the venturi being difficult to "make", the venturi give "differing" results in test guns, the venturi was expensive to make due to the difficulty and probably not market friendly. Also I seem to remember EK having his "favorite" due to the bullet "failure issue", and seem to remember it was a .333 OKH and that he carried for several years on his pack-in hunts. The .333 (if right) being a favorite because of the bullets working like he wanted them too.

There are probably some other guys here with better memory than mine on this. Maybe they will chime in with some info.

Anyway you go, you've got a "one of a kind" there, and congratulations on your ownership!

as to

Anybody remember who the "experts" were who were shooting for the 5000Fps mark. Last I heard from several years ago, they had given up due to impractical barrel length, and unforeseen problems with projectiles and other components.
___________________________________________________

I can't see a copper lead projectile holding up to that kind of speed. The lead would most likely melt.

AS to Newton; He never did figure out the variables of the speed of sound. In the vacuum of space, he is spot on. We don't live in space. Sound is not C.

Get a .22mag rimfire with a 22in tube. Then watch the group size change with the weather. It's the most fun barometer I have ever had.

The .17M2 is made to stay just under the M2 speed. If you have a 24in tube and your using the faster rounds you will most likely have some group size issues. If you have a 20in tube use the faster stuff. Check this out for yourselfs. Stay away from the .22mag rimfire unless your willing to to do this test.

|Muddog,

You are correct on the jacket/lead projectile. That was the first issue "problem" they ran into with the 4000 plus-FPS. I do remember they tried different projectile material.

Toward the end of their testing, they were using a saboted/titanium projectile and getting a little over 5000fps. Then they started having barrel erosion issues.

At that point, they kind of ended the article by saying back to the drawing board, and if they came up with anything practical they would try some testing. I wasn't too long after I read about this that out military came out with their "tank-killer" saboted projectile (about two years).

By the way, not criticizing the Mach2 cartridge, I think it is a nice cartridge. I just have the opnion the 17HMR is the more likely one to last.

Will try the "barometer" test on the .22 mags sometime this Summer. My most consistent/accurate .22 mag is a 20" barrel.

Whether the powder has already burned or not is irrelevant. It, or the gases, still have the same mass.

2525,

We had to go all the way to Australia to find it but we have found it... the truth. Thanks

Fans of overbore catridges such as myself can rest secure in the knowledge that the laws of physics continue to hold despite a mountain of bull**** to the contrary. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

John
Being a shooter and a gunbuilder, I have some experience to add your comments.

The 300 WSM is to the 300 Winchester what the 6PPC is to the old 6x47.

The 6x47 was a cantankerous round that sometimes shot and sometimes did not shoot--one had to work with them diligently to make them shoot well.---Take the same rifle and same barrel and make it into a 6PPC and it shot. The case capacity of the two rounds is very similar and the end velocity is similar. These results took the variables of action, stock, barrel etc out of the tests.

I have had great success with the 7 WSM and 300 WSM-they shoot and shoot well. I have no problems with them feeding through my actions or actions or actions I have modified.

Jim Borden

Jim--

I've had the same experience with the short-fat mags. They don't produce any more muzzle velocity than longer rounds of the same capacity--but the velocities they do produce are far more consistent.

Aside from the WSM's, I've also had extremely good luck with the 7mm SAUM. In fact I have gotten the best short-fat accuracy out of factory ammo with that round, which may or may not have anything to so with the factory Rem. 700 I was shooting it in.

Have also seen some phenomenal accuracy out of the WSSM's, but apparently very few people want to buy the rifles!

I have seen some problems with all the short-fats feeding in factory actions, but not many since the early days. They do seem to feed better in push-feed actions--but I have also seen a few push-feed actions with the feed rails just a little too far apart, so that the rounds popped out early.

Good to see you posting here!

John

Where in Manhattan are you? I am in the village. How did you get Elmer's rifle? Keith is a hero of mine. The 285 OKH was a cartridge that had a tube brazed over the flash hole so the powder was ignited from the shoulder back towards the rim as opposed to the other way as is normal. Supposed to make ipowder ignition more uniform resulting in faster and more accurate loads. The militaery was considering it vfor artillery ammo if I remember my reading right.

The Wal-Mart near me had several Winchester 70s in 223/243 WSSM that nobody wanted until word came out about USRA shutting down the New Haven, CT, plant. Now all the Winchesters have been sold or are on lay-away. I've been really happy with my 25 WSSMs, really, really, really, happy!

Jeff

I have not met Mic, but his collaborator on these cases is Vi Smalley, who is a acquiantence of mine and shoots at the range here in town. Two things you should know, if you are discounting these cases as marketing hype that ignores the laws of physics.
First, Vi is a rocket scientist. Truly--he retired from Thiokol were they make the shuttle boosters. I am willing to assume he knows a little more about combustion and gas flow than most of the rest of us. And no, he didn't do the O-rings.
Second, I have read their patent application. The case shape uses the mathmatical concept of the parabola, which has the property of reflecting anything back to a central point. It is the same physics that makes collecting antennae of all types work.

And I am familiar with the same research as Jim where barrels were chambered first in 6x47 and then shot better once rechambered for 6PPC. Like Jim, it and the combined experience of thousands of BR barrels shot by the most painstaking shooters in the country convinces me that case shape does matter.

So I am not willing to say that these cases are some hokum that cannot be explained based on my freshman physics course 25 years ago. To me, their design takes the short fat case, adds the new wrinkle of the parabolic shoulder, and that combination intrigues me.

John

Thanks for the reply. Gary Amatrudo and I redesigned the Remington style feedrails and feedramps for my Rimrock, Alpine and Timberline actions. I have performed those modifications successfully to Rem 700 actions to keep the rounds "under control" while they are being pushed forward.

In my opinion--these rounds are here to stay--i still remember when Doc and Ferris came out with PPC--the word around the BR circuit was that it was a folly and that the cartridge would not last.

Jim

Just an observation from the peanut gallery, but it is amusing to watch a discussion about an innovation in a group of people so traditional and conservative, they are probably trying to find someone to put their 8-track player in their truck...... <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> Dutch.

Utah708--

I believe his name is By Smalley. At least that is the way he signs the correspondence he's had with me. I am familiar with the concept of the parabolic shoulder, because I shot quite a few rounds out of one of the rifles chambered for By's round during the past few months.

So far, I am reserving judgement on whether the parabolic shoulder somehow allows more velocity from the same amount of powder space. Savage and Norma are evidently cooperating on the project, so we'll have pressure-tested data pretty soon. However, the results that By and Mic provided showed the case gained just about exactly the amount it should have over the .204 Ruger, given their different case capacities. (I measured the water capacity of both cases.)

All this, however, has nothing to do with the 6x47 and 6mm PPC. Shooting accurately and somehow gaining extra velocity from the came amount of powder space are two different things.

I have seen the finer accuracy from a number of short rounds, from the mundane .308 to all the PPC's, WSM's, WSSM's, SAUMs, etc. I have yet to see any increase in muzzle velocity due to case shape, but am perfectly willing (even eager) to learn about it if it has somehow been achieved.

MD

Jim--

I am certain the .300 WSM and .270 WSM are here to stay. I have hopes for the 7mm SAUM, but the WSSM's are apparently not selling very well at all--apparently partly because of some gossip about how the .223 WSSM ate barrels.

Another part of the problem may be that the average shooter can't find the accuracy advantages of the WSSM's in the typical factory rifle.

MD

savage 99, when the weather warms up a little I may take you up on that chronographing offer. Very kind of you.

Regarding the 223 WSSM Hornady did not do it any favors in its sixth edition citing significant throat erosion in 350 rounds and also stating it is hard on barrels with the word hard in bold italics. Of course they don't mention how fast they were throwing rounds through the barrel either and some of their data is pretty hot. I think this is some of the " misinformation" alluded to on Winchester's and Browning's site.

They also did not say how it would compare to a .22-250 or .220 Swift after 350 rounds.

I have been able to see "signs of throat erosion" in a .223 Remington barrel after 100 rounds, using a bore-scope.

MD