Home Forums Hunting & Shooting Ask The Gunwriters .308 accuracy again....

Ignorance and superstition will win out every time over scientific fact.

John, I did mention that it could have been someone else who wrote the artricle on " Inherent Accuracy" My aopologies however are offered.

Which brings up an interesting side discussiuon. " Which gun writers do we belive. " My answer would be that the ones that more closely match out own predjudices.

My thoughts on inherent accurate cartrdiges, are that some folks believe that particlar cartridges tend to be more accurate than others, and that as a whole you can take many rifles right out of the box, and that particular cartridge will more often than not prove to be more accurate than othes. I pesonnally believe that not enough data has ever been compiled to prove that theory in like manufactured rifles.

+1. That thread was meant to start a food fight, and it did.


Okie John

I brought up the M40X data as my proof for the .308s accuracy improvement over the .30-'06, but I forgot that Warren Page was the author. My Gun Digests from that era were discarded in one or another move (Navy career).

My second "proof" example comes from the Navy's Small Arms Training Unit (SATU) in San Diego. I was never attached there, but I spent copious time with sailors who were that I used to shoot with. The Garand M-1 was their preferred tool for military rifle matches, and they ended up rebarreling those '06 rifles to .308 Win because they shot better scores.

The SATU gunsmiths also developed M-1s in other cartridges including, 6 mm, 6.5 mm, and 7 mm. The .308 in those days bested them all as measured by scores shot "across the course".

Statistics are either for people not clever enough to solve the original problem, or quantum mechanics. <---humor

MD, I am content with Page's data. How about putting that up as an article on LoadData?

jim

What's a 308?

Safe Shooting! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Steve Redgwell
303british.com

Steve:

You are incorrigible . . . . . .

The 308 is what all of those Ishapore SMLEs are chambered for . . .(grin)

BMT

BY the Way, Steve:

have you heard anything about the Austrialian Tri-Star No 4 Mk 4 in 308? It is suppossed to be a new manufactured SMLE in 308 that tales M-14 magazines.

Sounds really cool!

BMT

I've only played with what I assumed were two prototypes a few years ago. Their release was plagued with problems. The price was also too high. Still, a person with too much money might bite.

Actually, I haven't bothered looking for at least a year.

Safe Shooting! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Steve Redgwell
303british.com

Got to think this through, MD. Lot of good stuff on here thought wise, and a tendency in many cases to wander from the original question.

I'm a believer in the "inherent" thing as applied to cartridges, just have seen demostrated too much, and when Bob Nosler speaks I listen.

My problem is with hearing so much of this argument, in one form or another over time, my reply is, "Show me?".

Will be back to this later, if you WANT to do article, think you could write it up as well as anyone, and hopefully better. If you DON'T want to do article, I'm convinced the inherent factor exists, at least until I've seen proven otherwise.

I hear tell that they are gonna go for $695 US. I would be interested in them as a very good battle rifle if they make reasonable provisions for a scope mount.

Can't say I WOULD buy one, just very interested.

BMT

For me �inherent� means that the accuracy potential is independent of the rifle. Prove accuracy is inherent to the cartridge not the round/rifle/shooter/moon phase combination. A trite but broad scoped cartridge comparison would do it for me.

There is enough past experimentation, time weighted expert opinion and experience with benchrest cartridges out there. Whatever cartridge has more of the things that are believed to contribute to accuracy, wins. Isn�t that how the PPC cartridges were discovered; inductive reasoning?

What I would do is make a list of cartridge design elements and loadings that contribute to accuracy. I would include relevant influences like powders, bullets; whatever, I�m no expert. The list can be based on anecdotal experience as long as there is enough anecdotal history. Note: �expert� opinion does have some weight with me.

I can start the list of possible things to compare:

1) Case geometry; shoulder angle, taper, case width/bore, expansion ratios, etc.
2) Powder efficiency, load densities (doesn�t the 308 get more mv per grain of same powder)
3) Primer factors?
4) Proclivity for available powders ( also which uses greater number of powders that are known to produce accuracy)
5) Quality of cases available, (already mentioned)

And so on�..

Inherent means �inbuilt�. If the 308 is more accurate, and I believe it is, a gunwriter should be able to articulate that to me without firing any more shots.

My own example in the 308�s favor: I have a 308 Remmy with a chamber so sloppy, oversized neck, I immediately sent it back to the factory thinking they would re-barrel. Well, they replied that it was within their factory tolerances. Back at the range and I found several loads that it would average sub MOA with. Inherent accuracy strikes again.

GM

I would suggest, to have a better comparison, using two barrels. Both full diameter, chambered in 30-06 and .308. Fire a predetermined number of groups or rounds and get a mean measurement of "group size". I don't pretend to know what that best measurement would be but measure something. Then cut back both barrels the same amount, rethread and rechamber for the other cartridge using the same reamers. That way each barrel is treated the to same mechanical stresses that might change the ability of the barrel to produce an accurate group. There will be two rifles but both cartridges will be shot out of each and hopefully reduce the variation caused by the platform.

Another way around would be to chamber a rifle in either .308 or 30-06 or even another round, fire a predeterimed number of groups or rounds. Then cut back the barrel but rechamber for the same cartridge and shot the same number of groups or rounds again. That would at least tell you if you needed to be worried about rechambering affecting the accuracy. It wouldn't tell you if the changes are the same for each and every cartridge but would at least tell you if the machining changes the group size.

A few thoughts.

Scott

John:

I applaud you for your desire to keep after this subject. It seems to me that you know a fact when you see one, but just can't get very many people to agree.

My view of the subject is that the 308's margin of victory (maybe 1/4 moa) over the 30-06 is smaller than the variation between rifles and loads (up to 3 MOA in good rifles).

Thus, you will never convince a majority of the people. Thier experience will differ from your conclusion.

It is the same problem that the US faced in teh 2000 election. George Bush won the election. BUT the margin of error in the voting was GREATER than the margin of victory.

To this day i know people who are convinced that Bush lost. No amount of statistical analysis, data review, etc. will change their mind. PERIOD.

So, I wish you luck in your endeavor,

BMT

Going back to the Remington/Page data . . .

In the .308 vs 30-06 thread I wrote that some indication of variation around the average group size was needed; MD questioned this in the post starting this thread. The point is worth exploration since it bears on how we interpret any similar data set. Gun writers produce a plethora of similar tables monthly, so this is not an angels-on-the-point-of-a-needle exchange. Here's a specific example using Page's data:

These average group sizes were reported for two of the .224 caliber cartridges:

• 0.387 - - 222 Rem Mag
• 0.400 - - 223 Rem

Page indicated that the maximum number of rifles tested in any one caliber was 150, so let's assume that these averages were developed with 150 rifles each. Based on the Remington data, do the two cartridges differ in accuracy? Stated another way, do these data demonstrate that the .223 Rem is more "inherently accurate" than the .222 Rem Mag?

More later.
--Bob

OK: Don't know enough to advise the "intricate" details of equipment and/or testing method as there are many who have more experience and knowledge.

However I feel such a test should:

1. Focus on the inherent characteristics of the cartridge, not the rifle or shooter. The rifle and shooter are responsible for the accuracy, as the cartridge already exists.

2. There should be standards established so that test may be repeated in case of new development, e.g. powders, bullets, priming, that could be considered inherent to the cartridge. In other words: cases similar to run out, primers same, powders that peak nearly the same for same velocity; this is where I'm perfectly happy with those who have experience and actual knowledge to design the "test".

3. Any such test that fit criteria above, should be referenced or included with new write-up for comparative review.

'Nuff said here, I think.

Do bullets have specific velocity window for optimal accuracy? If so, to make the comparison between the 06 and 08 more meaningful, wouldn't the cartridges have to be loaded to the same velocity for each bullet weight? And then if we did that, wouldn't that create a different operating pressures, intoducing further variables?

Or is this exercise akin to trying to determine how many angels can dance on the head of a pin?

I think the biggest variables in the real world are the skills and woodcraft of the driver. That's where the focus should lie IMHO.

That being said, this is one of the more intriguing intellectual exercises that I've seen.

BTW, I prefer Fords over Chevys and brunettes over blonds
<img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

Chris

Well, guys, we've gone too far now to back out. I just spent the afternoon on the phone with three guys who do know something about this--Melvin Forbes, Bob Nosler, and Charlie Sisk--and will spend time talking to more over the next few weeks. Got some VERY interesting information already, and suspect more will be forthcoming.

The article will not be on whether the .308 is more accurate than the .30-06, or whether any such differences (if they do exist) are practical. This is not an artiucle about practical accuracy. (I did one of those several years ago.) It probably will stir up lots of controversy, and not change anybody's mind that's already made up. But it will be fun!

MD

Sounds like a good crew!

What's controversy? Is there some on this site?

LOL!

I have shot both cartridges in target weight rifles enough to be convinced the 308 is certainly the more accurate of the two. I have shot a rifle using the same action with different barrels and have rechambered the same barrel. Even when the '06 shot very well, it did not shoot as well as the 308.
By the way, Steve, neither shot any better than my 303 in a similar rifle! In fact, it would seem the .303 has a definite edge on the '06.
I have built .308 benchrest rifles which most definitely did shoot better than my .303 but they were purpose built short range BR rifles.
There are some problems in attempting a valid test using the same barrel. Due to the difference in body taper it is necessary to set back to rechamber to 30-06 from 308. Due to the difference in cartridge length, it is,likewise, necessary to set back when going the other way. When you set back the barrel, you change the length slightly which introduces another variable.
In some forms of competition ("F" class for example) 1/4 moa is HUGE. So, a 1/4 moa advantage is certainly enough to swing the scale in favor of the 308. I suspect the advantage is at least that.
I suspect that cartridge design or shape has very little to do with accuracy. Similarily constructed rifles in .308, .303, 30-40 Krag, and 300 Savage all seem to work about the same if all else is equal (bullet quality, throat configuration, barrel quality. The rimmed cartridges are just a little more difficult to work with successfully. GD

Sounds great! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Can you include the 6.5's? We all know they're more accurate than any of the .30's <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

BullShooter:

Theoretically the Standard Deviation of Group CTC Ranges is directly proportional to the Expected Average Group Size. The ratio of Standard Deviation to Average Group Size varies with the number of Shots fired for Group. The ratios of Group Size Standard Deviations to Average Group Size for three, five, and ten shot Groups are 0.368, 0.267, and 0.191 respectively.

Assuming that the data for each caliber represents 150 five shot groups, a statistically significant (95% confidence) difference in Average Group Size would be about 0.023 inches for the .222 family of cartridges. So the difference between the .222 Mag. and the .223 is not statistically significant. The difference between the standard .222 and the .222 Mag. is statistically significant.

The above figures are not exact, as I am not a Statistician, but are good estimates.

Our conclusions will be no better than the quality of the supplied data. For example, the data would not be "fair" to the .223 if the .223's had 1/12" twist barrels while the other .22's were tested with 1/14" barrels. (Faster twists are known to exagerate the effect of any imperfections in bullets on group size.) Chamber to Cartridge Fit could certainly have an influence on the inherent accuracy of barrels, but it would be unfair to conclude that a cartridge was less accurate just because of a poorer reamer design.

Within reason, shorter barrels often exhibit better inherent accuracy than longer barrels, because they are relatively stiffer. If the 22-250's were tested with longer barrels, the data would unfairly represent their relative accuracy potential.

rollinghills