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Old November 17, 2012, 10:01 AM   #51
Bart B.
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Bart,my results were with 6 different rifles, 3 in 308 Win, and 3 in 30-06, never once could I match the velocity of the 30-06 load with the 308 Win, I ran into pressure problems before I could reach 2900fps with the 150 grain bullet in the 308.
That happens all the time when using barrels of the same (or within an inch or two] length. There was never any objective in the development of the 7.62 NATO and .308 Win. round to equal the velocity of a .30-06 for a given bullet weigh or barrel length. Close was good enough.

What about your comment:
Quote:
Now when both are loaded to standard military specs,they're pretty much equal,however,the 308 is close to max,where as the 30-06 is downloaded.
Please explain your reasoning on this.
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Old November 17, 2012, 11:35 AM   #52
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" But the vast majority of them stated the numbers in print as "psi" value when in fact it was copper (lead) units of pressure or CUP (LUP)"

Ah so. Danke.

As far as "downloaded" '06 ammo, my recollection of factory data from '50s/'60s was that the '06 was loaded to GI specs of around 49,000 psi, while the .308 was reported at 55,000 psi. I've no clue about today's loadings.

I'm lazy. I've been using the same loads in my '06 as back in 1950 when I first started. They work just fine, so why bother to change?

I get deeper dings in my 500-yard steel plate with my '06 than friends do with their .308s. Not enough to get excited about, but that's consistently been the case. Kinda hard for me to not believe that the '06 is generally a little bit stouter than the .308.
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Old November 17, 2012, 01:41 PM   #53
Bart B.
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Art...... Get today's loadings from the info below:

Please download the following for MIL SPEC info on military cartridges. Note they state "psi" for pressure but they used copper units of pressure; they should be "cup" to be correct:

http://www.everyspec.com/ARMY/TM-Tec...27_CHG-2_4432/

Then download SAAMI's document on cartridge specs. Starting at page 13, the cartridge pressure and velocity specs are listed. First for cup then later for psi numbers; very interesting indeed:

http://www.saami.org/specifications_...wnload/206.pdf

The info in the SAAMI document has excellent info on both pressure measuring types, techiques and specifications.

Of course, the .30-06 is "stouter" than the .308. It shoots bullets out faster given equal barrel and pressure numbers.

Last edited by Bart B.; November 17, 2012 at 10:44 PM.
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Old November 17, 2012, 08:24 PM   #54
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My '06 flings 168's at 2,940 fps, 175's at 2,820 fps, and 190's at a tick over 2,700 fps...24" factory barrel....I shot 308's for nearly 20 years, and I've never seen one approach the velocities I get with the 30-06 loaded to 63k psi in a modern bolt action.

Both are fine rounds...but the 30-06 is the more potent of the two.

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Old November 17, 2012, 09:29 PM   #55
Bart B.
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I've never seen one approach the velocities I get with the 30-06 loaded to 63k psi in a modern bolt action.
RidgeRunner, how'd you know the pressure was 63k psi; what did you measure it with? SAAMI's pressure limit for pressure transducer measurements on the .30-06 is 60,000 psi and its based on the limits of the .30-06 case. If you really had 63,000 psi, then it's quite possible standard average peak pressure loads for a .308 won't approach what that pressure produced.

Note that modern bolt actions will handle that much pressure for any cartridge. Some .308 Win. factory ammo has pressures at 63,000 psi as its case design's rated for 62,000 psi; the SAAMI spec which also has 66,000 psi for a maximum sample probable mean pressure.
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Old November 17, 2012, 10:30 PM   #56
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Old November 18, 2012, 12:04 PM   #57
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If the 30-06 case limit is 60k psi...explain how the 25-06 and 270 came to be, both are loaded well over 60k psi.

The SAAMI limit is based on something (probably older guns)...but its not the limits of that case.

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Old November 18, 2012, 02:16 PM   #58
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RidgeRunner, I'll answer your query.

Some of the commercial .30-06 match grade cases made by Winchester and Western Cartridge Company were made with thinner case walls than standard cases; typically 25 grains lighter than regular commercial cases and this frightened lots of folks. And some foriegn military .30-06 cases were not annealed to the specs that US military and commercial cases were/are.

Then there's the issue with low-numbered M1903 Springfields with not so well hardened receivers. SAAMI considered them when limiting peak pressure to 60,000 psi or 50,000 cup.

None of the other two commercial cartridges cases were made that way as far as I know. And the .308 Win.'s loaded to pressures higher than the .30-06 SAAMI spec, too, as are several belted case magnums.

Contact SAAMI then ask them as they set the spec; the guy there I've talked with over the years has answered my questions quite fast and well.

Still waiting on the answer to my question in post 55.

Last edited by Bart B.; November 18, 2012 at 02:56 PM.
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Old November 18, 2012, 03:04 PM   #59
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Would it really be relevant to the discussion if I answered with QuickLoad, SWAG, or even White Laboratories...the point was, that the properly loaded 30-06 can beat the 308 not by 100 fps...but by 200-300 fps, depending on bullet weight...and its perfectly safe to do so, in modern bolt actions.

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Old November 18, 2012, 03:15 PM   #60
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Originally Posted by Ridgerunner665
Would it really be relevant to the discussion if I answered with QuickLoad, SWAG, or even White Laboratories...the point was, that the properly loaded 30-06 can beat the 308 not by 100 fps...but by 200-300 fps, depending on bullet weight...and its perfectly safe to do so, in modern bolt actions.
Not according to QuickLoad it can't, not staying within SAAMI limits, which is the only definition of "safe" that matters.

The 30-06 gets about 150fps, max, over the .308, all else being equal to SAAMI spec.
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Old November 18, 2012, 09:42 PM   #61
Bart B.
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RidgeRunner, it's relavent if you just answer the question. If you didn't measure the pressure, then you're guessing or calculating from something that probably doesn't match your stuff. All you had to do was say so.

Meanwhile, I'll easily shoot bullets faster than a SAAMI or MIL SPEC peak pressure load for a .30-06 with a 172-gr. M2 match bullet standardized at 2640 fps with a MIL-SPEC proof load for the 7.62 NATO M60 round that uses that same 172-gr bullet atop 41 grains of IMR4475 (a 5.56 NATO powder) in a standard M80 round's case and its primer. Having shot a thousand or two of these in competition from Garands (yes, they take it in stride quite handily, several service teams used them in their M14's, too) and a couple dozen through a chronograph, they clocked at 2790 to 2830 fps on average from the M1 barrel used to test them.

But wait; there's more. . .So you could put together a MIL SPEC M1 .30-06 proof load with a LC case and primer and 52 grains of IMR4198 under a 172-gr. M2 bullet then out shoot the 7.62 NATO proof load above giving that bullet near 2900 fps from your .30-06.

Note that both these proof loads produce 67,500 to 71,000 cup pressure or approaching 80,000 psi in transducer systems.

And this leap-frogging could continue until the rifle blows; just like a low numbered 1903 Springfield did decades ago when a military unit tested one to see when it would blow up; it took a case half full of Bullseye pistol powder under a 172-gr. bullet to do it.

Meanwhile, let's stick to a SAAMI pressure standards to level the playing field (shooting range?). Which means the .30-06 has about a 100 - 125 fps advantage over a .308 Win.

Last edited by Bart B.; November 19, 2012 at 06:03 AM.
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Old November 21, 2012, 04:32 PM   #62
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If that matters to you as it does to me: the 308 is much less loud. Shorter case requires faster powder which causes max pressure earlier in the barrel and up to 25% less pressure at the muzzle. The target wont know the difference, your ears will over the years...
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Old November 21, 2012, 05:06 PM   #63
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The OAL limit of the .308 means that when bullets of over 175 gr are used the bullet must be seated deeply into the powder space reducing effective powder space.
For this reason the .30-06 is capable of handing the heavier bullets such as 200gr and heavier long range match bullets with much less pressure penalty at higher velocities.
The 1:10 twist rate of most .30-06 barrels is better suited to the longer heavier bullets than the 1:12-1:14 twist of .308 barrels.

While the original NATO ball load duplicated the original .30-06 ball, the 7.62/.308 is actually a refinement of the .300 Savage rather than a true all round replacement for the .30-06 as a sporting and long range target cartridge.

The Danes still use .30-06 rifles for their arctic circle patrols, the 06 being better medicine for polar bear than the .308.

PS
Standard commercial cartridge brass doesn't cold flow till pressures of 85,000 PSI or 68,000 CUP. Some cartridge brass can stand a good deal more.

PPS
Many low number Springfield blow ups were dure to defective subcontracted barrels. The barrels had been overheated during a bumping up process to from the shank end.
The burnt steel caused the chamber section to split breaking the receiver ring.
The same happened to an M-14 awhile back. Same cause, a defective aftermarket barrel.

The LN receivers were very hard but a bit brittle, even then almost all of the receivers that failed were from specific batches that had been overheated during the forging process.
One receiver that had held up the standard 75,000 CUP proof load and thousands of full power loads shattered like a jelly jar when a low pressure gallery/guard cartridge was fired. The low pressure did not expand the case well enough to grip the chamber walls, so the lugs took the full impact without delay.

PS
This spec sheet
http://www.everyspec.com/ARMY/TM-Tec...27_CHG-2_4432/
Contains several errors that are addressed in the spec sheets for procurement of propellents.
The M118 cartridge pressures are only expressed in CUP rather than PSI
M118 special ball (and the more recent M118 Long Range) has a pressure of 52,000 CUP (with max deviation of 57,000 CUP) rather than the 50,000 PSI listed in the above linked tech manual.
M80 has pressure of 48,000 CUP/50,000 PSI.

Last edited by Rainbow Demon; November 21, 2012 at 05:43 PM.
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Old November 21, 2012, 09:01 PM   #64
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The OAL limit of the .308 means that when bullets of over 175 gr are used the bullet must be seated deeply into the powder space reducing effective powder space.
For this reason the .30-06 is capable of handing the heavier bullets such as 200gr and heavier long range match bullets with much less pressure penalty at higher velocities.

The 1:10 twist rate of most .30-06 barrels is better suited to the longer heavier bullets than the 1:12-1:14 twist of .308 barrels.
Match bullets up to 250 grains have been used in .308 Win. chambers with long throats. Muzzle velocity from a 28 inch barrel's about 2150 fps. Needed a 1:8 twist to stabilize them through 1000 yards, but was very accurate when David Tubb used it in the late 1980's.

Military rifle teams shot 190-gr. Sierra HPMK's from 22 inch M14NM barrels and 24 inch M1 barrels with their standard 1:12 twist. Excellent accuracy with such loads that pushed them out at about 2450 fps for the USMC Rifle Team load of 41 grains of IMR3031 in an LC M118 primed case for their M14NM's. The USN and USAF used 44 grains of IMR4320 under the 190's in the same case and got about 2600 fps in their Garands. Both loads had peak pressures not to far from blue pill proof test loads; much higher than standard specs for the 7.62 NATO round. Both loads had the best accuracy at 1000 yards of any used in these semi autos.

When the .30-06 was "the" round for high power match rifle use, 1:11 or 1:12 twist barrels were favored for bullets from 168 to 200 grains if best accuracy was the objective.

Starting in 1963 it took only 2 to 3 years of .308 vs. .30-06 for the .308 to become the choice for matches up to 1000 yards by top classified shooters. The .308's 40% better accuracy was more advantageous than the .30-06's 10% less wind drift.

Last edited by Bart B.; November 22, 2012 at 12:38 AM.
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Old November 22, 2012, 02:52 AM   #65
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Match bullets up to 250 grains have been used in .308 Win. chambers with long throats. Muzzle velocity from a 28 inch barrel's about 2150 fps. Needed a 1:8 twist to stabilize them through 1000 yards, but was very accurate when David Tubb used it in the late 1980's.
Would the long throat be due to seating the bullet far beyond the specified cartridge OAL?
If so the cartridge would probably not feed from the magazine of most purpose built .308 length actions or military detachable box magazines.
Some 7.62 sniper rifles are built on .30-06 length actions, but would need the throat deepened for over length loads.

Quote:
Both loads had peak pressures not to far from blue pill proof test loads; much higher than standard specs for the 7.62 NATO round.
Which was what I was getting at.
A load that beats a match rifle to death in a fraction of the normal useful life is not much of a bargin unless Uncle Sugar is paying the bills.
Then again many match shooters of the thirties and earlier used hi nitro powders that destroyed the accuracy of expensive matchgrade barrels within 300 rounds, but they were willing to pay the price for a very slight edge in accuracy.

I suspect that any noticable accuracy advantage of .308 match rifles was due more to lack of interest in keeping the .30-06 competitive. The new kid on the block was getting all the development funding.
Improved low nitro double base powders may have been part of it. The .30-06 having performed better with single base powders during WW2 and before.
Double base powders tested in 06 matchgrade ammo had some of the best mean radius figures yet the next lot would have mean radius inferior to the single base powders. Single base was far more consistent from one lot to the next than available double base in those days.
Throat erosion was still a problem with double base at the time, with ten percent shorter barrel life.
The garand also operated better with the gas port pressure of single base, and there was less erosion of gas ports.
The .308 was developed from ground up to accomodate double base powders, and the M-14 was designed to handle the hotter DB ball powders by use of chrome lined bores and high temperature resistent alloy in the gas system.

The .308 with its smaller capacity would have an advantage if kept within its normal performance range, just as specialized target rounds like the 8.15X46R or .32-40 had at closer ranges. Consistency within a certain envelope outweighing maximum performance figures.
The .308 is much like the .303 British in some respects, and a number of UK shooters have told of the most accurate .308 loads being basically a balistic duplicate of .303 matchgrade loads.

With maximum ranges of 1200 yards in recent matches some have found the hotter long range .308 loads to be too much for some older match rifles, especially the converted No.4 rifles.
A few more modern .308 match rifles have also been damaged by the top end loads needed to keep the bullet super sonic at 1200 yards to avoid transition shock.

I'm no barrel maker but seems to me that the 1:10 twist developed for the 1903 .30 and the .303 when both used bullets of 215-220 grains should still be best for bullets in this range or heavier.
They did not keep the 1:10 twist because of any expectation that it would be optimal for the 150 gr .30 or the 174 gr .303, though the lightweight nose plug of the MkVII bullet meant the length was practically the same as that of the 225 gr Swift matchgrade bullet and benefitted from the tighter twist.

A bullet of 200 gr or heavier being more accurate in a 1:11-1:12 twist barrel than in a 1:10 twist is counter intuitive.
There must be more to that story than twist alone.

Last edited by Rainbow Demon; November 22, 2012 at 03:18 AM.
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Old November 22, 2012, 08:54 AM   #66
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Would the (.308 Win.) long throat be due to seating the bullet far beyond the specified cartridge OAL?
Yes.

Quote:
If so the cartridge would probably not feed from the magazine of most purpose built .308 length actions or military detachable box magazines. Some 7.62 sniper rifles are built on .30-06 length actions, but would need the throat deepened for over length loads.
The first .308 bolt action rifle was built on a standard length action with a spacer at the back of it’s .30-06 length box magazine. But the first USA made military sniper rifle was made using the Rem. 700 short action; same one their commercial version used. Best shots in the Army and Marine Corps wanted the Win. 70 action to be used as it was more reliable, stiffer and easier to maintain in the field than the Rem. 700. But Winchester was in dire financial straits at the time and Uncle Sam didn’t want to take a chance with them.

Quote:
A load that beats a match rifle to death in a fraction of the normal useful life is not much of a bargin unless Uncle Sugar is paying the bills.
Uncle Sugar spent zero dollars more maintaining M1 and M14NM rifles shooting those ultra hot loads. Properly built and op rods bent and fit to tight specs did not suffer. I’ve shot thousands of those loads and there were no problems.

Quote:
Then again many match shooters of the thirties and earlier used hi nitro powders that destroyed the accuracy of expensive matchgrade barrels within 300 rounds, but they were willing to pay the price for a very slight edge in accuracy.
Yes, and Hi Vel No. 2 was the favorite powder in the early 20th century and a good barrel for the M1903's from the DCM cost about $2.00. Those barrels lasted about 500 to 800 rounds of best accuracy.

Quote:
I suspect that any noticable accuracy advantage of .308 match rifles was due more to lack of interest in keeping the .30-06 competitive. The new kid on the block was getting all the development funding.
There was no development funding. When the 26-year-old “new kid on the block” using one in match rifle competition in the 1963 Nationals chambered his Hart barrel with a standard SAAMI spec reamer, it tested to sub 4" groups at 600 yards using the same powder, bullets and bore/groove specs as the .30-06. He won the Nationals with it that year. The best .30-06 match rifles of the day shot about 6 inches at 600 yards with the best bullets available. A few years later when Sierra changed over to hollow point match bullets instead of FMJBT ones, the .308's accuracy dropped to 3" or better at 600 and the ‘06 to about 5" The .308's no better now with the best bullets available and that then-new kid’s still building them today.

The difference in accuracy was the specs for the leade angles; the .308's was less and distorted bullets less as they entered the rifling. Later tests with the .30-06 with leade’s having the same 1.5 degree leade angle proved there was not any significant difference in accuracy. But the longer barrel life and milder recoil of the .308 made it easier to shoot accuratly and at a lower cost.

Quote:
Improved low nitro double base powders may have been part of it. The .30-06 having performed better with single base powders during WW2 and before. Double base powders tested in 06 match grade ammo had some of the best mean radius figures yet the next lot would have mean radius inferior to the single base powders. Single base was far more consistent from one lot to the next than available double base in those days.
I’m not aware of any double base (ball) powders being tried in 30 caliber M72 match ammo. Some Winchester ball powders were used in 7.62 NATO M118 match ammo in the late 1970's and its ho-hum accuracy of even the best lots were a disappointment to competitors.
Quote:
The garand also operated better with the gas port pressure of single base, and there was less erosion of gas ports.
Gas port erosion was never an issue with even service grade M1 or M14 rifles. The bore wore out for service accuracy standards at 8,000 to 10,000 rounds of both. Match grade barrels were typically replaced at 4000 to 5000 rounds.

Quote:
The .308 was developed from ground up to accomodate double base powders, and the M-14 was designed to handle the hotter DB ball powders by use of chrome lined bores and high temperature resistent alloy in the gas system.
Peak pressure specs for both 7.62 NATO and the 30 caliber M1 round were 50,000 CUP when the 7.62 NATO hit the street. Winchester chose to spec the .308's peak pressure at 52,000 CUP, same as their .270 Win. round, as it would be used in more modern rifles like the .270 was; and SAAMI bought the idea.

Quote:
The .308 with its smaller capacity would have an advantage if kept within its normal performance range, just as specialized target rounds like the 8.15X46R or .32-40 had at closer ranges. Consistency within a certain envelope outweighing maximum performance figures.
There was (and still is) no difference in accuracy with the .308 with reduced loads compared to full power ones. The 300 metre international free rifle folks liked mild loads for their .308's as the milder recoil made them easier to shoot accurate. Full power loads in NRA match rifles bested out at 300 yards with equal accuracy of about 1/3 MOA in the best of them. Nothing to date's equalled what a .308 did in 1971 shooting sub 1.5 inch 10-shot groups at 600 yards.

Quote:
The .308 is much like the .303 British in some respects, and a number of UK shooters have told of the most accurate .308 loads being basically a balistic duplicate of .303 matchgrade loads.
Note that the Brits use a different set of objectives in their fullbore long range matches. They’ve always insisted on leveling the playing (shooting?) field by making everyone shoot the same ammo. Arsenal ammo was used and still is. Handloads are not allowed. Good lots from Great Britian’s Radway Green Arsenal shot very well even with huge muzzle velocity spreads due to compensation of the SMLE’s barrel whip making long range accuracy much better than a Mauser action based rifle.

Quote:
With maximum ranges of 1200 yards in recent matches some have found the hotter long range .308 loads to be too much for some older match rifles, especially the converted No.4 rifles. A few more modern .308 match rifles have also been damaged by the top end loads needed to keep the bullet super sonic at 1200 yards to avoid transition shock.
Which is why George Swenson, a British gunsmith, designed and made the Swing 4-lug single shot action in 1972. The British 7.62 NATO loads had a lower muzzle velocity spread and their SMLE’s rebarreled for that round didn’t shoot it all that accurate. That Swing action was the forerunner of more modern Paramount, RPA, Barnard, Musgrave and other single shot .308 Win. actions used in the Commonwealth’s fullbore matches. They kicked the pants off the USA 2-lug Winchester and Remington actions for accuracy with new cases from anywhere.

Quote:
I'm no barrel maker but seems to me that the 1:10 twist developed for the 1903 .30 and the .303 when both used bullets of 215-220 grains should still be best for bullets in this range or heavier. They did not keep the 1:10 twist because of any expectation that it would be optimal for the 150 gr .30 or the 174 gr .303, though the lightweight nose plug of the MkVII bullet meant the length was practically the same as that of the 225 gr Swift match grade bullet and benefitted from the tighter twist. A bullet of 200 gr or heavier being more accurate in a 1:11-1:12 twist barrel than in a 1:10 twist is counter intuitive. There must be more to that story than twist alone.
There is more. It’s the speed they leave the barrel at. Muzzle velocity and twist rate determine the rpm’s a bullet spins at. A given bullet weight and shape for a given caliber needs to be spun in a narrow velocity range to stabilize it well throughout its flight. Ballistic engineers at Frankfort Arsenal developing the 7.62 NATO round and the same folks at Winchester developing their .308 round knew the 150-gr. ball bullet from the .30-06 was spun too fast going out the barrel for best accuracy through 1000 yards. Harry Pope (famed barrel maker of the early 20th century) also knew a 1:10 twist was too fast for in the .30-06 Palma rifle barrels shooting 150-gr. bullets he made for the US Palma Team around 1920. They all used 1:12 twists for those barrels.

The Brits used 1:13 and 1:14 twist barrels in their fullbore long range match rifle 30 inch barrels shooting arsenal ammo’s 147-gr. FMJBT bullets. Bullets left at 2900 + fps and remained supersonic through 1000 yards. That slower rpm rate didn’t cause accuracy problems with bullets a bit unbalanced which is common in arsenal ammo. Spinning bullets too fast makes those even with a slight unbalance jump off the muzzle axis as the exit the barrel. Even today, benchresters adjust their charge weights for shorter ranges to make muzzle velocity just fast enough for the atmospehric conditions to stablize them for best accuracy at the lowest rpm rate that works. Best example's the .30BR shooting 115 to 135 grain bullets out around 3000 fps from 1:15 to 1:18 twist barrels.

Last edited by Bart B.; November 22, 2012 at 10:33 AM.
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Old November 25, 2012, 08:43 PM   #67
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Call me a Sally, but both the 06 and 308 kick too much for my taste, at least when my .270 will drop anything I care to hunt.
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