What makes the 30-06 less accurate then the 308 or any other round for that matter .

[B.L.E.]

Don't .50 caliber Barrett sniper rifles, used for those ultra long range kills, use a cartridge that's essentially a scaled up .30-06 round?

I think there's a lot of getting cause and effect backwards in this world. A cartridge gets a reputation for accuracy and so all the serious target shooters gravitate to that cartridge and all the best rifles are chambered for that cartridge and that re-inforces the reputation making it sort of a self fulfilling prophecy.

[Cheapshooter]

Why is it the 30-06 is not so accurate ? I don't understand what makes this round so inferior to the 308 when it comes to accuracy .

The Internet!!! and people who believe everything they read on It.

[Jimro]

Don't .50 caliber Barrett sniper rifles, used for those ultra long range kills, use a cartridge that's essentially a scaled up .30-06 round?

You must be thinking of the 338 Lapua which holds the longest confirmed kill record. The .mil uses a 50 cal sniper rifle because Ronnie Barrett made one and there was nothing else that could do what it did. Even Carlos Hathcock's famous "Ma Deuce" sniper shot was simply because that was what he had. Milspec 50 cal ammo has instability issues around 1400 meters depending on atmospherics, and anything less than that it is 3 MOA at best. Most of the "long shots with 50 cals" I've dug into are really a sniper shooting at a mortar team and managing to hit one of the insurgents, with the exception of the Canadians who actually procure true match grade ammo for their rifles.

When Palma made the 308 rifle to be used in 30 cal that end any competition on anything else being used.

30-06 is still legal for Service Rifle, but when was the last time you saw a Garand shooter make Presidents Hundred?

The difference in accuracy is slight, and like anything that involves statistical overlap over large datasets you will find very accurate 30-06s and poor 308s. But what keeps replacing what in the winner's circle is a better indicator of accuracy potential than "well my rifle does this!"

Jimro

[kraigwy]

What makes the 30-06 less accurate then the 308

Nothing.

[cw308]

Sounds like it's Bart B's turn in the barrel. I feel he knows what he's talking about. Being in the service, Served in VN 9th Inf. The M14 & M60 both 308 cal. both could reach out and toutch someone at long distances. I'm sure the Military had good reason to change from 30-06 to 308 (7.62) Keep up the good info Bart B. I'll always have your 6. Chris

[MattShlock]

I was wondering if this thread was started to start a fight!?

[Mobuck]

My statement was in reference to the OP. I don't think many shooters are good enough to determine a real world difference in accuracy between 30/06 and 308. In addition, there is just too much variation even between identical rifles. To prove the statement would require a vast amount of shooting with a wide variety of rifles identical except in chambering to establish a baseline before even starting to develop data proving the .30/06 is a less accurate cartridge than the 308.

[Metal god]

I was wondering if this thread was started to start a fight!?

Not even a little bit . I really wanted to understand why some think the 30-06 is less accurate . If you would like to read the thread that got me thinking about it and where I got the quote .

Here it is - It's a long thread and covers many areas of long range shooting . The last three post is where I got the idea to start this thread
http://thefiringline.com/forums/show...=527393&page=3

[jmr40]

I think you misunderstood Bart's intent. Most guys are perfectly content with a hunting rifle that will put 3 shots into 1" at 100 yards. Using that criteria there is really no real world difference. But for many benchrest shooters their goal is .1". It takes a rifle 10X more accurate, and many simply cannot conceive the difference. My gunsmith shoots some benchrest and has several targets framed in his shop with 5 shots @ 100 yards measuring in the .09" range.

At first glance saying a 308 is 30% more accurate seems impossible, but a group .15" is 50% larger than a .1" group.

The way the OP is worded makes it seem that you thought a 308 is far more accurate. I don't think there is any doubt that it offers an edge in accuracy. The real debate is how much, and does it really matter to the individual shooter.

[dakota.potts]

I've heard the trajectory is not as flat because of the heavier bullet weight. Not sure if that's true but it makes sense at face value

[Metal god]

The way the OP is worded makes it seem that you thought a 308 is far more accurate. I don't think there is any doubt that it offers an edge in accuracy. The real debate is how much, and does it really matter to the individual shooter.

Yes that is what I was taking from the quote . ( the 308 is 30% more accurate ) and that just did not seem right so I asked here . When you put up the numbers you just did . How you explained it makes much more sense

for bench rest shooters their goal is .1". It takes a rifle 10X more accurate, and many simply cannot conceive the difference.

Although not new to firearms I am some what new to shooting with extreme accuracy . I forget some times that there are guys out there that the .1 moa is a big deal and can notice it . I don't think I'll every be that good or even want to try but there was a point that I thought shooting a soda can at 100yds was accurate . Now If I'm not putting the round through the mouth of the can I'm not happy so maybe some day I'll try to get that .1 moa difference out of my firearms .

[Dan Newberry]

In short, though this will no doubt get lost in the noise here... it's *recoil*...

There is no reason the 30-06 can't be just as accurate as the 308, but it's the recoil control that makes the difference. If one can control the recoil, then the two cartridges are equally accurate.

[Sarge]

OF all the factors that determine whether a specific rifle is accurate, 'caliber' has to rank pretty low on the totem pole.

[MattShlock]

"I don't think there is any doubt that it offers an edge in accuracy. The real debate is how much..."

I have doubt and question the whole premise to be honest!

[Bart B.]

Facts follow . . . . . .

The 7.62 NATO case was made with sharper shoulder angle to minimize shoulder setback from impact from bolt closure and firing pin forces. Improved accuracy due to more consistent primer performance. .30-06 cases often had shoulder setback's of .006" when chambered and fired. Round developed from .300 Savage cases bought from Winchester and Remington. Shorter, fatter powder charges burned more uniformly.

.308 match ammo made by Western Cartridge Company (headstamps WCC58 with 200-gr. FMJBT and WCC60 with 197-gr. HPBT) was most accurate commercial match ammo ever made.

Sierra’s new 168-gr Int’l bullet shot most accurate in their rail guns from .308 Win. barrels. First 30 caliber cartridge to shoot repeatable sub 2/10ths inch groups in their 100 yard test range. First ever to shoot some test groups under 1/10th inch. Sierra then used .308 cases to test all 30 caliber bullets 180-gr. and lighter. Commercial sporting rifles chambered in .308 shot more accurate than those in .30-06 used to develop load data for their 30 caliber bullets used in the .308. All from Martin Hull, Sierra's first ballastic tech who loaded and tested the ammo used for their bullets.

US Army 300 metre free rifle teams used .308's in late 1950's to win Olympic and other international matches; was the most accurate centerfire round they tested. Winchester made solid bottom single shot M70 receivers with oval loading port on right side for their free rifles. Better accuracy than any other cartridge they used.

Ferris Pindell (Sierra Bullets’ tool & die maker) used .308 with 168's to win benchrest matches in late 1950's. Shorter, fatter case accuracy was his and Dr. Palmisano basis for their PPC ones starting in 1974.

.308 first used in 1963 at NRA high power Nationals winning the championship.

Lake City and Frankfort arsenal’s 7.62 NATO XM/M118 match ammo bested M72 30 caliber stuff smaller many-shot test groups in late 1963. 2.16" mean radius (about 6.5" extreme spread) for M72 versus 1.82" mean radius (about 5.5" extreme spread) for M118. Many dozens of shots per test group were shot. Ballistics engineer at Lake City arsenal told me in the early '70's the M118 match stuff was typically 25% more accurate overall than the M72 match ammo.

In late 1963, several dozen top ranked (best of the master classified) high power rifle competitors rebarreled their match-winning record-setting Win. 70's from .30-06 to .308 Win. Best accuracy with .30-06 and Sierra’s newest and most accurate 168's and 190's was 5 to 6 inches at 600 yards. Same quality barrels in same Win. 70 long actions built in 1952 for the .308 with ½ inch spacer in magazine and on extractor clamping ring, most shot 4 to 5 inches, some in the 3 to 4 inch range and a few under 3 inches.

1964 to 1965, virtually all the high power bolt action match rifle records set with the .30-06 gave way to the .308 cartridge besting them. .308's better accuracy caused too many unbreakable ties on the old military/NRA high power V-bull targets. USN’s and USAF’s 7.62 NATO converted Garands built identical to the .30-06 ones shot 20 to 30 percent smaller groups in their 300 yard test range.

NRA changed 200 to 600 yard high power targets’ scoring ring sizes to smaller ones in 1966. The 1000 yard target’s rings were reduced in 1972 as the .308 accuracy at long range out scored the .30-06.

Machine rest tests of .308 reloads at 600 yards in 1971 were 1/3 the size of anything the .30-06 ever produced. Match bullet weights up to 250 grains have been used with much success in competition.

.30-06 was allowed for use in Palma matches from about 1989 to 1992. Nobody built one that consistently out scored the .308's.

Virtually all the “most accurate” cartridges use powder charge weights equal to 1 grain for each square millimeter of the bore’s cross sectional area. Both PPC ones used in benchrest and the .308 are probably the best examples.

Non-believers of the above can contact those still alive of the dozens that did the tests, won the matches and set the records in the first 10 to 15 years of the .308's use in shoulder fired rifle matches by switching from the '06 to the .308 then hear it directly as I did. I've been there, done that and heard their own experiences after watching them do it learning how to do it as well.

Meanwhile, chamber a barrel with a .30-06 reamer with a 1 degree leade angle and it'll shoot almost as accurate as a .308.

[Art Eatman]

My recollection is that the .308 was the first computer-aided design. Among design parameters, they had to figure out ways to improve consistency of the powder burn rate. That led to the present case dimensions. Another factor was that the powder give a pressure curve such that they could get approximately 2,800 ft/sec with a 150-grain bullet from a barrel of around 20". This was achieved with a chamber pressure of some 55,000 psi (I've no idea of how many CUPs this is.) By the way, that pressure is about 5,000 to 6,000 psi greater than the factory loadings of the '06 in the 1950s.

Shorter action = stiffer. Shorter barrel = stiffer. Stiffer means better consistency in the harmonics.

Add it all up and you have a better cartridge than the '06 for certain purposes. IMO, it's not better for some purposes beyond target shooting on paper or military sniper use. In some situations, it's as good as the '06; in some, it falls behind. No big deal. Figure out which need fits what scenario.

[Metal god]

Thanks Bart for the detailed explanation . It appears history has shown the 308 to be more accurate then the 30-06 . It also appears that the difference is quite small when measured in MOA and most would never notice . It also appears that just about everybody in this thread is correct in there view of the 308 and 30-06 to a point .

Now that it appears the question has been answered . I'd like to look at another aspect of accuracy and that is recoil . Does recoil it self make a gun less accurate . I've heard the 308 will recoil about 3/8 of a inch before the bullet leaves the barrel ? Would a 375 H&H recoil more then 3/8 of a inch before the bullet leaves the barrel ? What about a 22-250 ? I would think the velocity would play a big roll in how much the rifle moves before the bullet leaves the barrel . Is it the rifle that is less accurate or is it really the ability of the shooter to shoot the rifle accurately ?

Again is it the recoil it self that makes a firearm less accurate or is it more to do with the shooter being able to handle the recoil ?

I ask cus I hear guys talking about heavy recoiling rifle being less accurate . They almost always caveat it with the the ability of the shooter . IMHO the rifle is accurate or not and how well a person can shoot that rifle does not say anything to how well the rifle shoots . I can shoot sub MOA with my Ruger American 308 but my buddy can't .There's to much recoil for him to relax enough to shoot it accurately . That does not mean the rifle is less accurate cus of recoil . It just means he is less accurate with a heavy recoiling rifle . yes ?

[Bart B.]

Old Roper comments on some sights used on Palma rifles:

They have lens in the front sight can't have them in the rear sights think is 5x on front lens.

Current NRA high power rifle rules do not allow magnifying iron sight lens elements; it takes 2 lenses to magnify the target. Nor have such sights been allowed in any Palma match I know or shot in. Some smallbore matches allow magnifying metallic sights.

Those Rightsight +.25, +.5, and +.75 diopter corrective lenses and other makes and diopters only corrrect for the shooters vision so the target appears sharper when their aiming eye's reasonably focused on the front sight. Some folks use lenses in rear sights to make the front sight sharper. And some rear sight adustable apertures have adjustable diopter settings.

A diopter is a way of expessing a lens' focal length. 1 diopter equals 1000 millimeters (one meter); 1 divided by the diopter number equals the lens' focal length. A +.25 diopter lens has a focal length of 4 meters. A 2 diopter lens has a focal length of half a meter; 500mm.

And also the following:

When Palma made the 308 rifle to be used in 30 cal that end any competition on anything else being used.

Since it has no competition who's to say it's better? If it was the best why didn't US Palma scope the 308. Myself you put a lens which is available in power magnification in the front sight might as well scope the rifle then you add one of these
http://www.sinclairintl.com/optics/s...prod44975.aspx

The reason the Palma rifle cartridge was limited to the .308 was to be the same as other country's rifles used in International Palma Matches; an expansion of the British Commonwealth's use of only the 7.62 NATO round. This was hoped to get more folks used to shooting that cartridge at 800 through 1000 yards.

Sinclair's AOS Microsight front sight device is not allowed in Palma matches if it magnifies the target. As it has " two tiny, internal lenses" I think that disqualifies it as the NRA high power rules only allows one lens to be used.

And in respons to the following:

I think Bart was talking about F-Class rifles and no bearing on the real world of shooting. When they open the F-Class sure didn't see a rush to scope 308 so that got to tell you something.

I've never been to, much less fired a round, in any F-class match. I have used F-class shooting positions to test rifles and ammo for accuracy. Lots of folks did that decades before F-class was established as a competitive discipline. I was referring to NRA high power match rifle shooting where no rests are allowed and all's done shooting standing, sitting or kneeling and prone holding the rifle to ones shoulder. That's the closest competitive shooting discipline to the real world of shooting. . .to me, that is.

That lack of a rush to scope 308 tells me folks wanted to use some other cartridge and some of the 600-yard benchrest favorites were popular. I've no idea what they thought the accuracy of a .308 Win. might be when fired in the positions they used. But they probably didn't think it was all that great. Most "group" shooters have no idea whatsoever that "score" shooters' hardware will equal theirs when tested under the same conditions; that's beyond their comprehension and understandably so. I've never held that against them; it's pretty much human nature in my opinion.

[Bart B.]

Metal god, the more recoil a rifle has while the bullet's going down the barrel, the more the bore axis will move off where it was pointed when the round got smacked by the primer and fired the bullet. That's 'cause the recoil axis is not in line with the butt pad center against your shoulder. You gotta hold a smallbore target rifle perfectly still 3 times longer than a .308 to shoot good scores. This is the reason a rifle's bore axis does not point exactly to a spot above the aiming point equal to bullet drop plus sight height above bore axis when they're zeroed by the shooter. They're all off a bit by some angular amount and direction.

And if the rifle's not shouldered exactly the same way for each shot, that alone will cause the muzzle axis to vary its direction for each shot fired. This is the reason several people shooting the same rifle will have different zeros for each load they use in it; they each hold the rifle differently and their body's are not all the same shape, size and makup.

Tube guns whose recoil axis is better aligned with the butt pad-shoulder center move less during recoil. I believe this is one reason why they shoot more accurate than conventionally stocked rifles.

Recoil energy formulas are easy to find on the web. Here's a decent one with rifle weights and cartridges already listed:

http://www.chuckhawks.com/recoil_table.htm

How massive the person is holding it as well as how hard against their shoulder the rifle's held determines the distance backwards the rifle's going to move. And the angle the bore axis is to the shooter's body also has some effect.

40 plus caliber double rifles shooting 500 grain plus bullets have their muzzle axes toed in so they cross at 10 to 30 yards downrange. Left barrel firing swings the rifle to the left, right to the right. The barrels are "regulated" to do shoot to point of aim at 50 or 75 or whatever yard line the customer wants. Look at one sometime and note the bore centers are closer together at the muzzle than the chamber centers at the breech.

Hand gun front sights' tops are higher above the bore axis than the rear sight tops (square notch and square post types) for the same reasons.

[MattShlock]

Bart B. -- interesting, if not persuasive, factoids. Thanks.

That .30-06 reaming you reference -- does that coincide much, if at all, with the .30-06 Ackley Improved chamber then accuracy-wise do you know? I believe these favor some bullet weights...

[Bart B.]

MattSchlock, I've no idea on anything about an Ackley improved chamber except their only objective is (in my opinion) to get as much velocity possible from a standard case blown out as much as the brass will allow and still clean up the original chamber. But their larger and more angled shoulder area will better hold the case in place when the firing pin strikes them and that's a plus for accuracy as well as case life.

[RevGeo]

I find it hard to believe that the minuscule difference in felt recoil between a .308 and a 30-06 (given the same rifle model and weight) can be much of a determining factor in the relative accuracy of the two rounds.
I've been shooting both calibers for almost 50 years and I just don't believe it.

[Art Eatman]

Figuring comparative recoil is easy enough.

Add the powder and the bullet weights and multiply by the muzzle velocity, for the cartridges under consideration. Then look at the ratio between them. If the rifles are of equal weight, you then know the comparable recoil between the two.

If the rifles are of different weight, just figure that ratio and add it to the ratio from above.

[Bart B.]

RevGeo, the felt recoil difference between any two cartridges in otherwise identical rifles has nothing to do with the relative of either the rifles or the cartridges. As long as the rifle's held exactly the same way for each shot, it doesn't matter how much recoil it has; accuracy of the rifle and ammo will be pristine, excellent, match winning and very small game dropping.

It only effects the ability of the shooter to keep the rifle from moving while the bullet goes down the barrel. That's when the small recoil difference between the .30-06 and .308 makes the .308 a tiny bit easier to shoot accuratly. And it's only about 5% of the total recoil and mostly imperceptable. It's the jet effect of high pressure gas shooting out the muzzle after the bullet's left the muzzle that causes 95% of felt recoil.

That barrel time recoil's enough to cause problems. Mostly when slung up in prone and the shooter's front elbow on the ground and the front hand's under the fore end. If that elbow's moved in any direction after first keeping it in place to get a zero, the next shot will not shoot to zero; typically to the left or right.

Also, when slung up in prone, if the rifle's butt doesn't get back into the same position for each shot, vertical shot stringing will occur. Shots go high if the butt's too low in the shoulder; low if too high. The muzzle axis elevation angle's not the same for each shot.

Both of the above can easily cause a 1 MOA error; sometimes more. This is one of the main reasons why medium size 26 caliber cartridges are now the favorite for long range prone matches; the big belted magnums would shoot bullets just as accurate but the barrel time recoil was a lot more and the rifle moved more off from where it should point during barrel time recoil.

Most folks will never see this happen, but to the few who can, it's important to deal with.

[Metal god]

OK art I did your math thing here with what to me would be common rounds/loads . All loads were on the hotter side of powder .

69gr 223 = 75,069

175gr 308 = 104,245

190gr 30-06 = 117,970

300gr 338 Lapua = 207,000

As you can see the recoil goes up the chart as you would expect . How ever when i use Mag Pro powder with the the bullet wight and same velocity as the above 30-06 the number comes out to 142,800 . So you have the same bullet , same case , same velocity but more powder and you get quite a bit more recoil . Is that right or am I doing something wrong . The Mag Pro is a slower burning powder so does that make for more recoil ? I would think the slower the powder burns the less felt recoil you would have . For lack of a better term . The slower powder would feel more like a push then a kick ?

I'm not saying I know this , It just sounds right to me