What exactly is "inherent" accuracy in regards to a cartridge?

[Zaydok Allen]

Another thread raised a question in my mind. I often hear "XXXX cartridge is inherently accurate." This makes no sense to me. A firearm may be inherently accurate based on how it was put together. A design may offer a certain level of inherent accuracy over another because of some particular material use or other design element. A particular loading may be inherently accurate, out of a particular gun, but again, that is based on the load and firearm combination, not a particular cartridge.

So I asserted the below quote.

For my own knowledge, what exactly makes a particular cartridge more "inherently" accurate than others? I'm asking, not being snide.

I'm a firm believer that with proper rifling in the barrel, a quality revolver or semiautomatic that is built to tight tolerances, and with a quality example of a particular cartridge, any cartridge can be fired accurately. Particular bullets are harder to stabilize certainly, but with the right barrel, it can be done.

I guess what I'm saying is that the word "inherent" is often applied to a cartridge. In the end, all center fire cartridges consist of a bullet, a casing, powder, and a primer. Inherent accuracy does not exist when it comes to cartridges. It can only exist in firearms, and firearm designs, as that is the real variable being discussed.

Now, inherently more accurate loadings can certainly exist based on bullet diameter, shape, powder choice, powder quantity. However, that is still based on the current available platform's to fire it.

If I'm missing something, please share. I don't role my own loads, so I admit I may be off on this. Maybe, I should start a different thread on the subject.

Can a particular cartridge be "inherently" accurate, and if so, what exactly makes that possible or true? It's important to note I'm talking about cartridges here in a general sense, like 9mm or 45 acp, or 357 magnum, not particular loadings.

So what does the group think? If I'm wrong, please educate me.

inherent is defined in Webster's New World Dictionary (Third College Edition)as : adj. existing in someone or something as a natural and inseparable quality, characteristic, or right; innate, basic, inborn

 

[ArchAngelCD]

You're not alone. I never understood how a cartridge could be considered "inherently" accurate either...

 

[Nom de Forum]

One aspect of inherent accuracy in regard to a cartridge is about how its design influences the propellent burning characteristics for the most consistent burn. If you look at cartridge case specifically designed for bench rest rifle shooting you will see they tend to relatively short and large in diameter compared to the bullet diameter. They also do not have much empty space for the propellent move about in side the case. Having a case neck that provides good support of the bullet also helps. What this thread needs is an experienced benchrest shooter to post as I am not one of those and have only a slight knowledge of cartridge design. I suspect power space usage in pistol cartridges also greatly contributes to inherent accuracy.

 

[Panzerschwein]

I've heard that .38 special is "inherently" accurate as well, but I don't know what it means either!

 

[tipoc]

"inherent accuracy" is a loose term that is inherently inaccurate in that what it can mean varies from shooter to shooter.

It's also a term that comes from rifle shooting and that can only loosely apply to pistols or revolvers. A lot of terms we toss around are like that.

The best it can mean is that all or most of the many factors that go into accuracy meet up.

I'll give an example: The development of smokeless powder meant it took less powder to get a bullet moving faster (among other things). This meant a revolution in the design of both bullets and cases and rifles. By the 1890s pointed jacketed bullets with a boat tail shape, a spitzer bullet as I recall off the top of my head, came into being and "overnight" the round nosed exposed lead bullets of the 30/40 Krag and others became obsolete for military purposes. The new bullets were "inherently" more accurate over a longer distance and higher velocity than the older style.

Sectional density: A bullet with a good sectional density will tend to be more accurate over a longer distance than one with a less impressive S.D. This is not really a factor at 25 or 50 yards or less, meaning with handguns. Some folks think it makes a difference in penetration once a hit is made but that's another discussion. It can make a distance in long range handgun shooting. Thus a bullet with good S.D. is "inherently" more accurate

Bullet shape: A decade or two back NATO changed the shape of the 9mm bullet from a rounder profile to a more pointed shaped. This is with their FMJ ammo. This improved accuracy in their tests at 50 yards and beyond. Thus the shape of a bullet can improve it's accuracy "inherently".

Weight and loadings: We can fire a 158 gr. bullet from a 38 Super with good speed and accuracy with the right load. But not from a 9mm or a 357 Sig. With the 9mm the case does not have the capacity. With the 357 Sig the short neck becomes a factor. Accuracy will suffer. Some maintain that the 40 S&W is "inherently" less accurate than the 10mm with heavier bullets because of this. But with the right weight bullet, correct rate of twist of the barrel and a good gun and shooter those rounds and other are accurate.

Balance: Folks will speak of a "balanced" load for a handgun. Meaning that the bullet weight, velocity, muzzle flash, actual and felt recoil match up for a very shootable gun and thus enhance accuracy. The 38 Special is considered an "inherently accurate" round. It's just hard to beat the "inherent accuracy" of the K frame S&W and the 38 Special, like pancakes and syrup, bread and butter, just perfection. So is the 357 Mag.

Often when folks speak of "inherent accuracy" they are looking at one or more of the above characteristics, or others, and are speaking in a shorthand kind or way.

tipoc

 

[Thermactor]

I think the aerodynamics, weight distribution, stabilization, density, and so on of a particular round have everything to do with accuracy and that is to a big extent baked into the design.
Hence why certain rounds are more consistent, need less holdover, etc, to hit a target at long ranges. (338 Lapua exemplifies these desirable qualities)
How well it crosses the transonic region makes a big difference too.
When was the last time you attended a 7.62x39 benchrest competition?

 

[CLP]

One aspect of inherent accuracy in regard to a cartridge is about how its design influences the propellent burning characteristics for the most consistent burn. If you look at cartridge case specifically designed for bench rest rifle shooting you will see they tend to relatively short and large in diameter compared to the bullet diameter. They also do not have much empty space for the propellent move about in side the case. Having a case neck that provides good support of the bullet also helps. What this thread needs is an experienced benchrest shooter to post as I am not one of those and have only a slight knowledge of cartridge design. I suspect power space usage in pistol cartridges also greatly contributes to inherent accuracy.

I like this answer. Of course there are exceptions to the rule (eg 300 Win Mag)

 

[fanchisimo]

I think ballistic coefficient of the bullet itself is in there too, but I only have a very basic understanding of what it is. I just know the higher the number the better it flies and can ignore wind.

 

[ColtPythonElite]

I don't think it a scientific term. I would say if you could track down the history of the term, it is just some jargon a gun writer coined in a gun rag years ago. More or less, I just think it means more times than not the accuracy suits the major of the people who shoot it.

 

[SilentStalker]

An inherently accurate round generally means one that is straight shooting and has a very good ballistic coefficient. This term usually applies to long range shooting with a rifle. I have never heard of someone apply it to a pistol cartridge. Some cartridges are more flat shooting and have a better ballistic coefficient than say another cartridge thereby making it inherently more accurate than other cartridges, if that makes any sense. If you want to get deep into it check out a book called Applied Ballistics by Bryan Litz.

I might also add that an inherently accurate round means that the bullet itself being propelled out of the muzzle at 3000fps or faster can cut the wind better, meaning its not as effected by wind as much as other rounds. A good example is a 6CM, .243 pretty much any of the 6mm crowd is very efficient at cutting through wind which makes them inherently more accurate than say a .308WIN. I hope that helps some.

The 105 grain Berger Hybrids I generally shoot have a BC of .547 vs. .462 with a 175grain SMK shot from a .308WIN. the higher the BC the more accurate the round...in a manner of speaking.

 

[22-rimfire]

"inherent accuracy" is a loose term that is inherently inaccurate in that what it can mean varies from shooter to shooter.

I agree with this unless you are talking about 41 magnums of course.

Some shooters seem to be more inherently accurate than others. That seems like a fair statement.

 

[Nom de Forum]

I see things being posted about bullet characteristics, velocity, flat shooting, cutting the wind, etc. and than is not what makes one particular cartridge more accurate than another if you have two cartridges that are different in case size, but are equal in quality of consistent manufacture, that are shooting the exact same bullet in caliber, bullet weight, bullet construction, an equal maximum velocity. What cartridge do you think is going to be the most inherently accurate that meets the criteria listed in the preceding sentence, a 6mm PPC or a .243 Win? Here is a hint: Nobody wins benchrest competitions consistently (if ever it has been done) by shooting .243 Win against competitors shooting 6mm PPC. This has to be because the 6mm PPC is an inherently more accurate cartridge because of its design. These two cartridges shoot the same caliber of bullet and the .243 can be loaded to match the velocity of the slower velocity of the 6mm PPC.

 

[Skribs]

I think it is somewhat subjective, but I've understood that it's not necessarily about how consistent the bullet is, but how easy it is to adjust to changes in wind or distance. It also has to do with relativity compared with other cartridges that would be used in similar platforms.

For example, the 6.5mm grendel is inherently accurate because it has a much higher degree of energy than other AR-15 rounds.

 

[Nom de Forum]

I think it is somewhat subjective, but I've understood that it's not necessarily about how consistent the bullet is, but how easy it is to adjust to changes in wind or distance. It also has to do with relativity compared with other cartridges that would be used in similar platforms.

For example, the 6.5mm grendel is inherently accurate because it has a much higher degree of energy than other AR-15 rounds.

This is not true. No offense, but higher energy levels do not make a cartridge inherently more accurate. A 6mm PPC has far less energy than a .243 Winchester. Accuracy is about consistency in shots fired at a specified distance where environmental factors equally effect the two competing cartridges. At 100yards these would be the same for the 6mm PPC and .243 Win. At 500 yards the slower, but maximum velocity loaded, 6mm PPC bullet would have more flight time for the environmental factor of wind to affect consistent shot placement than a faster, maximum velocity loaded, .243 Win bullet. Even with that it would not surprise me that a 6mm PPC would still be more accurate.

 

[Skribs]

Maybe what I said was an oversimplification. However, I do know people like the 6.5 for long range accuracy, compared to others that they prefer for SD (5.56, 6.8, 300 BO). It is true that 6.5 has more energy. I specifically mentioned energy because it's slightly less velocity than 5.56, but at a much greater weight so it retains that velocity over distance. So if I just mentioned velocity (which it has over the others mentioned) then it would be inaccurate.

My point was more that the 6.5 is the "accurate" AR round compared with the others, at the very least in terms of why people purchase it. It's "accurate" because relative to the competition, it easier to use at longer range.

 

[jamesjames]

Please correct me if I'm indulging in another internet myth...

But what i had head in the past as I got into shooting big bore six guns and especially single action armys was that Elmer Keith used to say that the .44 special was inherently more accurate than the .45 long colt. His interest in hot-rodding the .44 special led eventually to the development of the .44 magnum. We all know that story.

the other part of the story that we don't know is why he thought the .44 special was inherently more accurate. the story I gleaned from gun magazines and internet posts and such (see the coming fallacy?) is that the Colt SAAs of the time were being made on old, worn tooling, and that the chamber throats were too big and/or irregularly sized. that led to the SAA in .45 long colt not grouping very well.

Meanwhile, the Colt SAA's chambered in .44 special shot tighter groupings. And it turnede out that the chamber throats were bored to closer tolereances, mostly because fewer had been made and the tooling was was not worn out on that line.

Like i said, please correct me if i'm wrong, but that's the story I heard.

 

[ColeK]

460Kodiak,
I have not read any of the other post.
I have never heard of an “inherently accurate” pistol cartridge.
I hear on rifle forums "XXXX cartridge is inherently accurate."
I agree with you that there is no such thing as “inherently accurate” cartridge.
But, there are cartridges that are easier to get to shot well, if you are willing too spend the time and money.

 

[MachIVshooter]

But, there are cartridges that are easier to get to shot well, if you are willing too spend the time and money.

That's pretty much it.

"Inherently accurate" is more appropriately described as "less difficult to attain precision with"

Basically been said already, but deserves reiterating:

Certain calibers have better availability of bullets that are conducive to accuracy. You'll find more match grade bullets in .244", .264" and .284" than in .257" and .277". Doesn't mean the .243, 6mm rem, .260, 6.5mm RM, 6.5x55, 7mm-08, .280, 7mm RM, 7mm WSM, etc. are more accurate cartridges than the .257 Robert, .25-06, .257 wthby, .270 win, .270 WSM and the like. It just means that you're going to have more options for bullets that your barrel likes in the former diameters.

Some cartridges have a design that gives a more even, consistent burn with a wider range of powders. Usually, the shorter & fatter powder columns get more uniform ignition and burn than the long skinny ones. So, once again, your range of powders to choose from to find a load your rifle likes is broader.

Some case designs center themselves in the chamber (bullet/throat alignment) better than others. This can be negated by neck sizing when hand loading, but if limited to factory ammunition, a straighter walled rimless case with a sharper shoulder, such as the WSM, RSAUM, PPC and BR rounds, is going to be less prone to lying at an angle in the chamber than a more heavily tapered rimmed case or belted magnum like the 7.62x54R or .300 H&H mag.

To a lesser degree, cases with longer necks are also more conducive to developing accurate loads, giving greater flexibility of seating depth.

And all else being equal, rounds for which only single shot and bolt action guns are available are likely to develop a reputation for greater accuracy than those most often found in lever action or semi-automatic designs.

Likewise, expensive ammunition that is only manufactured with high quality brass and bullets will be reputedly more accurate than rounds which are often loaded with less expensive components and in far greater quantities.

So in the end one can see that, while no cartridge is actually more inherently accurate than another, there are quite a few variables that, as said above, make it easier to find an accurate load for one round than another.

 

[notaglockfanboy]

the higher the BC the more accurate the round...in a manner of speaking.

That is not a accurate statement at all. You can take the same bullet, which is what the possesses the BC not the round it is fired from, and it will shoot as bad as the most inaccurate rifle out there if not combined with the best powder charge, seating depth, etc in that particular cartridge. BC has noting to do with how accurate a cartridge is, it has to do with how well that particular bullet bucks wind and retains velocity at long distances.

 

[SilentStalker]

Yes, everything I said was a gross oversimplification. As someone else posted, I think the best example of what it means is that some rounds are easier to be precise with than others. You can make any round accurate once you find what the rifle likes, i.e. seating depth, powder load, bullet weight, etc. Again, if anyone wants to learn more about this kind of stuff check out Applied Ballistics...

 

[jerkface11]

No such thing as an inherently accurate round. You can make anything shoot tiny groups.

 

[Zaydok Allen]

So far this thread is a very interesting read, and I see in some regards I was correct. Some of the points brought up make good sense when it comes down to potential for particular cartridges to be loaded in a way that will generate good accuracy and precision. It still sounds as if "inherently accurate" is a bit of a misnomer, and really a misrepresentation of reality. It is more concise though it would appear.

I guess that is my point when it comes down to it. My original post quote was made in a response to this quote. I guess I'm curious what you gents think about this as it is in regards to pistol cartridges.

There are some cartridges which are more inherently accurate than average.(For example. .32 long.38 special. .44 Russian, 44 special and .44 magnum are known to have above average potential accuracy in revolvers. Th PPC benchrest cartridges were actually designed for max POTENTIAL accuracy from a bolt action rifle. The actual accuracy of a particular firearm/cartridge combo is always a shoot and see proposition-every gun is a law unto itself. That being said, the 9x19 does not make the list for max INHERENT accuracy but it is not a problematic cartridge that fights against accuracy(there have been a few such as the .32-20). It is pretty easy to find 9mm gun and load combos that are more accurate than even above average shooters.

Comments? I'm trying to learn here, not just be right. So keep going because this is good info to have out there. It seems the implied potential associated with the term "inherently accurate" is much more appropriate for rifle cartridges.

 

[Nom de Forum]

That's pretty much it.

"Inherently accurate" is more appropriately described as "less difficult to attain precision with"

Basically been said already, but deserves reiterating:

Certain calibers have better availability of bullets that are conducive to accuracy. You'll find more match grade bullets in .244", .264" and .284" than in .257" and .277". Doesn't mean the .243, 6mm rem, .260, 6.5mm RM, 6.5x55, 7mm-08, .280, 7mm RM, 7mm WSM, etc. are more accurate cartridges than the .257 Robert, .25-06, .257 wthby, .270 win, .270 WSM and the like. It just means that you're going to have more options for bullets that your barrel likes in the former diameters.

Some cartridges have a design that gives a more even, consistent burn with a wider range of powders. Usually, the shorter & fatter powder columns get more uniform ignition and burn than the long skinny ones. So, once again, your range of powders to choose from to find a load your rifle likes is broader.

Some case designs center themselves in the chamber (bullet/throat alignment) better than others. This can be negated by neck sizing when hand loading, but if limited to factory ammunition, a straighter walled rimless case with a sharper shoulder, such as the WSM, RSAUM, PPC and BR rounds, is going to be less prone to lying at an angle in the chamber than a more heavily tapered rimmed case or belted magnum like the 7.62x54R or .300 H&H mag.

To a lesser degree, cases with longer necks are also more conducive to developing accurate loads, giving greater flexibility of seating depth.

And all else being equal, rounds for which only single shot and bolt action guns are available are likely to develop a reputation for greater accuracy than those most often found in lever action or semi-automatic designs.

Likewise, expensive ammunition that is only manufactured with high quality brass and bullets will be reputedly more accurate than rounds which are often loaded with less expensive components and in far greater quantities.

So in the end one can see that, while no cartridge is actually more inherently accurate than another, there are quite a few variables that, as said above, make it easier to find an accurate load for one round than another.

Great job of explaining the variables that effect accuracy. I do have to disagree with the part of your last statement I placed in bold. As I posted earlier, if all other things are equal in quality in two cartridges and the platforms they are shot in, one will be inherently more accurate. I am using the word inherent as meaning one of those cartridges will consistently shoot more accurately than the other. If this was not true there would be much greater variability in the cartridges used to compete in brenchrest rifle shooting. There are extremely well made cases and bullets available for the .243 Winchester and so many powder options to choose from if it were possible to load a .243 cartridge that equaled the accuracy of the 6mm PPC it would be well known. If the 6mm PPC is known for more accuracy than the .243 Win, I think that is a strong indication it is an inherently more accurate cartridge.

 

[Nom de Forum]

No such thing as an inherently accurate round. You can make anything shoot tiny groups.

Sure you can, but some always seem to consistently win in contests requiring the smallest groups.

 

[Skribs]

Think of it like this. Which objects are inherently deadly, between a machine gun, a hammer, and a consumer reports magazine?

The machine gun is obviously deadly.
The hammer is not purpose built for destruction, but it is quite capable of it.
The magazine is generally only deadly to household arthropods, but Jason Bourne could still kill you with it.

I hope this is a good metaphor for the inherent accuracy of bullets. Some are easier to shoot accurately, some are marketed that way, but they all have potential in the right hands.