Inherent accuracy?

10 June 2010, 23:08

wistrapper

Inherent accuracy?

I've read articles in different periodicals and reloading manuals that suggest the .222 and .308 Win as being "Inherently Accurate". What is it about them that make them inherently more accurate than another cartridge of the same caliber?

10 June 2010, 23:21

Paul B

I wish somebody would tell me as well.

Sounds like a bullshit word used by writers who are getting paid so much per word and a way to pack the article for a few pennies more.

Paul B.

10 June 2010, 23:24

wasbeeman

Don't know but I assume it's their accomadating nature and balance. When it doesn't seem to matter what you pour into the cases, the rifle digests it and does a good job with it.
I can think of half a dozen cartridges or more that can be loaded to the same preformance level with several different powders/bullets/primers/cases, etc. It just doesn't seem to matter.
And then a couple ie .225win & 25-06, come to mind that have such a narrow performance window that you can end up talking to yourself.

10 June 2010, 23:31

vapodog

quote:
Originally posted by wistrapper:
I've read articles in different periodicals and reloading manuals that suggest the .222 and .308 Win as being "Inherently Accurate". What is it about them that make them inherently more accurate than another cartridge of the same caliber?

IMO it's all BS....the assumption that something about them has "inherited" a characteristic simply defies logic.

I won't deny that both the cartridges listed are typically accurate but so is the .243, the .220 S, the .25-06, the .264, the .223, the .17 rimfires, and the list goes on and on!

Some might say that the .30-30 isn't "inherently" accurate.....put it in a finely tuned bolt rifle and see what it does!!!!!

Inherently accurate and "insipient" case separation are totally misunderstood....both terms should be deleted.....but they persist...

BTW...."insipient" means simply "the early signs".....

11 June 2010, 01:36

BECoole

Yeah, I think some cartridges are more inherently accurate than others. Here's what Bart Bobbitt has to say about it: 308 vs. 30/06

One factor Bart sometimes mentions is shoulder angle. Sharper shoulders headspace more positively and this contributes to better accuracy.

Plus, I think this guy is onto something: Superior Ballistics, Inc.

11 June 2010, 02:53

MFD

Several years ago had the opportunity to read a report of tests conducted by NATO regarding inherent/potential accuracy of various rounds and the ratings were whether they were capapble of a 1,2,3,etc. grouping. 1 being one tenth, 2 tenths, and so on. 7.62/308 was scored as a 1 round and believe the 223 was as well. There were some others in that range, but not very many. Supposedly the test was done over a 10,000 rnd. duration(not the same barrel I was told) and Lapua brass and rifle was Rem.40X. No load or bullet data was provided and I was able to purchase quite a bit of the once fired brass. Still using some of it today. This took place some 20 years ago and sure today other cartridges would also produce such results.

11 June 2010, 02:56

duckboat

For most shooters, the difference is too small to notice, but there is no doubt that some cartridges are inherently more accurate than others. High level benchrest shooters have proven that for many decades. The 222 was king for a number of years and now other cartridges have surpassed it. Again, the differences are slight, but there is no doubt that it is true.

11 June 2010, 05:44

craigster

Both are very accurate, I think the designers knew what they were doing, but they also got real lucky.

11 June 2010, 17:28

wistrapper

BEcoole,
Cool article by Mr. Bobbitt. Looks like the guys at Superior have done their homework too.

Thanks to everyone contributing. As to be expected there is a lot of guys here with a lot great experience and information.
Brad

11 June 2010, 18:19

mho

Although the concept of "inherent accuracy" is somewhat elusive, IMHO there is little doubt there is some truth involved.

To your lineup of .222 Rem and .308 Win it would be more than fair to add calibres such as 6mm PPC etc.

Problem is, to conclusively prove a cartridge "inherent accurate", you'd have to test such a large number of rifles and calibers that you'd be able to show statistical significant differences in (average?) accuracy. Hard job...

- mike

11 June 2010, 18:36

jeffeosso

some cases are more effeceint, i believe .. but inherently accurate? i tend to disagree .. after all, the 300 HH has NONE of the characteristics normally assocaited with inherently accurate, but still turns in great groups ..

and a 416 rigby shouldnt be, but is generaly 1/2 moa

11 June 2010, 18:50

Bernie P.

No BS about it.Case design is crucial to a cartridges "inherent accuracy".Just take a look at the bench rest record books and see how the 6m PPC kicks butt.It has set more records than any other cartridge in history.It's little brother the 22PPC uses the same case and dominates it's class.Many of the newer cartridges are based on their design-short/fat.

11 June 2010, 20:09

MikeMichalski

I'm not going to say the "BS" comment is "BS" or not, but if some cartridges were "inherently" more accurate than the others, we would all be shooting the most "inherently" accurate ones. The rest would be history (not).

12 June 2010, 00:03

JTEX

quote:
No BS about it.Case design is crucial to a cartridges "inherent accuracy".Just take a look at the bench rest record books and see how the 6m PPC kicks butt.It has set more records than any other cartridge in history.It's little brother the 22PPC uses the same case and dominates it's class.Many of the newer cartridges are based on their design-short/fat.

I have to agree with this post YES some cartrige designs ARE more inherently accurate than others.

That's why more records have been set with th PPC than others.

12 June 2010, 00:23

jeffeosso

with respect, i disagree. IMHO

what i am hearing is if you made a 1" long 22PPC, it would be more accurate than a 22PPC? is that the myth we are talking about?

the ppc is a great round, without a doubt. But where is the "short and fat" part adding to accuracy? there's several round fatter, and several shorter ..

We have NOT seen marked accuracy improvements of the 300wsm to the 300win nor the 25 WSSM to the 25-06, have we? and the 25wssm is certainly both short and fat.

if short and fat meant SQUAT a 22BR or WSSM would be MORE accurate than a 22PPC ..

base to bore ratio (fat)
BR 2.09
WSSM 2.455
PPC 1.98

length to bore
BR 6.78
WSSM 7.456
PPC 6.72

a large part of bench shoot is the SHOOTER ..
the VERY MILD recoil of a PPC might add to the shooters skill, though

easy enough to prove .. make a 1" long 22PPC case rifle and see if it shoots BETTER than a standard 22PPC .. if it does, there might be something to it

if it doesn't, then its just pantherpiss

13 June 2010, 18:16

Bernie P.

I think it's a matter of hitting on just the right case dimensions through careful trial,error,and analysis along with the rest involved in load development.I suspect it took years of this before Palmisano and Pindell finally settled on their two rounds as we know them today.

13 June 2010, 23:33

SlamFire

Bart Bobbit was shooting when the 308 came onto the target scene.

Accuracy is quite relative. In the post Bart posted on thefiringline.com, he says a 30-06 will hold 6 inches at 600 yards, a 308 half that.

I wish I could keep all my shots within six inches at 600 yards, but even if I was shooting straight for all those shots, that thing called the wind blows bullets around. I challenge anyone with any handheld rifle to keep 20 shots within six inches at 600 yards.

http://thefiringline.com/forum...ight=308#post3588028

quote:
July 11, 2009, 11:46 PM #15
Bart B.
Senior Member

A friend of mine was the first person to shoot the .308 Win. in high power competition at the 1963 Nationals when it was first allowed. He won the Nationals by a handy margin and repeated it a few more times the next several years. The most accurate .30-06 bolt action match rifles at the time would hold about 5 to 6 inches at 600 yards. .308's would shoot about half that. The accuracy .308's had over the .30-06 caused so many unbreakable ties for the next three years, the NRA had to reduce the scoring ring sizes on targets to separate the outstanding scores from the excellent ones.

Meanwhile, the USN Small Arms Match Conditioning Unit got a batch of 7.62 NATO chambered 1:12 twist Garand barrels from the government's Springfield Armory then put them in a series of match conditioned M1's. Accuracy was about half of what the best 30-06 Garands produced. These Garands (also used by the USAF) shot more accurate than the other services M14NM rifles; it took the other services a few years to catch up. By the 1970's, both M1 and M14NM match versions would shoot inside 4 inches at 600 yards from accuracy cradles. The best 30 caliber Garands any of the services could build held about 8 inches at 600 yards.

Lake City Arsenal, after developing match ammo for this new round immediately noted M118 7.62 NATO stuff shot better than M72 30 caliber match ammo. Sierra Bullets used to use the .300 Savage case to test their 30 caliber bullets until the .308 Win. came out; they switched.

.308 Win. ammo from match rifles made with Win. 70 actions have shot smaller groups testing rifles and ammo at 600 yards smaller than most bench rest records at that range; .75 to 1.5 inch 10-shot groups for example. No .30-06 bullets from any barrel has even come close. Given a choice between either cartridge when both were allowed in US Palma rifles for 800 to 1000 yard matches, the best shots always chose the .308 as it was the most accurate and had less vertical shot stringing.

And though Winchester got the first contract to make thousands of 7.62 NATO ammo and commercialized the round as the .308 Win., they didn't develop it. Remington's Mike Walker (benchrest champ, designer of the .222 Rem.) headed the team of folks modifying the .300 Savage case to withstand full auto cycling. I believe they were working with Frankfort Arsenal in this cartridge development.

Bullets as heavy as 250 grains have been shot from .308's winning 1000 yard matches doing so. Not too shabby for exiting the 1:8 twist barrel at only 2150 fps.

Most of the accuracy difference between these cartridges was caused by the leade angle in the chamber's throat; 2.5 degrees for the .30-06 but only 1.5 degrees for the .308. The .308's shorter powder charge helped as well as more shoulder area and sharper angle reduced shoulder set back when the firing pin slammed the case forward in the chamber resulting in more uniform primer detonation. A .30-06 with a 1.5 degree leade angle and ammo with uniform muzzle velocity may shoot as accurate nowadays as a .308. But the milder recoil during barrel time a .308 has makes it easier to shoot accurately.

14 June 2010, 00:42

Jim C. <><

quote:
What is it about them that make them inherently more accurate than another cartridge of the same caliber?

No one is sure why, but some cartridges do exhibit better accuracy than would seem likely. But if it was a simple formula all the cartridge makers would jump on it and produce a line of super accurate ammo. Actually, it means so little as to be irrelivant to most of us.

Spending money for a quality barrel and fitting it in a well stocked quality action will improve accuracy much more quickly and surely than messing with the chamber.

To the tiny degree "inherent accuracy" is true requires averaging a lot of rifles in any given cartrige and the use of a precision caliper to demonstrate even a slight "average" difference.

14 June 2010, 01:09

Krochus

I once built a stevens 200 around a shilen select match bbl with the express purpose of cambering it on a cartridge generally viewed as being as inherently INACCURATE as possible.. 7.62x39mm

It would regularly shoot groups in the .2's

IME inherent accuracy based on the cartridge shape is a complete load of bullshit. However when you take into account the quality of components and gear to load for that cartridge there may indeed be a kernel to truth.

The rifle, load and quality of components matter. Whats stamped on the casehead does not