Lerch says: "Well then explain to me how a large, heavy, bull barrel that is so much stiffer would be less accurate than a barrel that is skinnier than a willow branch???"
If both have the same bore, groove, twist and chamber dimensions as well as the same ammo used, I don't think there would be any difference in accuracy. People who have measured (not guessed) how a barrel whips vertically when fired know there is only one whip. It's much like the wave in a bull whip when it's flung out across a male bovine's backside. As long as the bullet leaves the barrel at about the same place in that single whip, it will go to the same small cluster of shots previously fired.
Lerch also says: "Not to mention that all of the benchrest shooters and extreme range enthusiasts shoot barrels that look like sewer pipes!!"
That's not quite true albeit a popular belief among rifle shooters. If one checks out the barrel dimensions of folks on Palma teams around the world as well as folks in the USA shooting prone rifles in 600 and 1000 yard matches, they'll learn those barrels are skinnier and more whippy than the 'sewer pipes' used in bench rest matches. Yet the accuracy they attain when fired under equal conditions are all equal.
Bill Bailey says: "I think the whole key here is CAN BE as accurate. With out a doubt there are skinny bbls out there that have shot some great groups. The problem is the load has to be precisely tuned to the bbl. The skinny bbl WILL NOT shoot as good, day in and day out under varying temps and atmospheric conditions using the same load. Could you tune the load for every condition? Sure you could, but who wants to have ump-teen different loads when you could just have a heavier bbl that will vibrate w/a much lower magnitude that will shoot the SAME LOAD into respectable groups under most all conditions. Now you still may have to have a summer and winter load, but 20-30 degrees won't make much difference."
The above is a very common (popular) belief. Consider what happened in 1991. The US Palma Team Captain asked in late 1990 if I and several other former Palma team members would help develop the ammo to be used for the 1992 World Long Range and Palma Championships. As this match was to be held at the NRA range at Raton, New Mexico, all the ammo had to be supplied by the USA; everybody would shoot the same stuff. The host country always supplies the ammo.
Our criteria was simple, use new .308 Win. cases, Federal 210M primers, metered (not weighed) powder charges of several powder makes and types, then seat Sierra Bullet's then a prototype .3084-in. diameter 155-gr. Palma bullet to an OAL of 2.80 inches. We all used various powders including RE15, AA2520, IMR4895, IMR4320, WW748 and a couple others I now forget. These loads were tested in several Palma rifles with different actions but all had 5- to 6-pound 30-inch barrels with tapers much like those I mentioned earlier about 1.2 inches at the back and about .800 at the muzzle. Bore diameters ranged from .2980- to .2995-in., groove diameters from .3065- to .3075-in. Mine was .2980 and .3070. Bullet runout on our development loads was mostly in the .001- to .003-in. range. We shot our ammo at 1000 yards with both aperture and scope sights. After each of us had shot a few 20-shot strings with each load, it was easy to tell which ones shot great and which ones didn't. The load selected was 45.3 grains of IMR4895.
Winchester said they would make the cases but our ammo master said he wanted to go to their plant and check tolerances before the production run was made for a few hundred thousand cases. The plant had to change their case forming dies and setup three or four times to get body and neck wall thickness tolerances down where we wanted them. But the results were worth it. Those cases were probably the most uniform made since the famous WCC58 and WCC60 stuff Western Cartridge Company made for the US Olympic Team's free rifles.
Two Dillon 1050 progressive machines made the ammo. One resized just the necks so bullet grip would be uniform and seated the 210M primers. The other 1050 metered powder and seated bullets. While our ammo man's two sons were busy cranking out ammo, he randomly grabbed 22 rounds one day then took them to his local 600 yard range to test them. He clamped his Winchester 70 Palma rifle in a machine rest, fired two shots to center the group on a target, then fired 20 consecutive shots in about 15 minutes. That 20-shot group was shown in a 1991 issue of Handloader Magazine; it measured about 2.7 inches between widest centers. Not too shabby for ammo with powder charges having a 3/10ths grain spread and bullet runout up to .004-in. And the first time that barrel had shot that ammo.
Samples of all our test loads were sent to a ballistics lab. The ammo with the lowest muzzle velocity spread, smallest charge weight spread and most uniform chamber pressures used AA2520 ball powder. That load was also the worst for accuracy in all the test rifles. Only average spreads in muzzle velocity, charge weight and peak pressure happened in the selected load using IMR4895. But it was the most accurate.
In the summer of 1991 at a big long range match at the NRA Whittington Center south of Raton, NM, several thousand rounds of that load were made available to rifle shooters to compete in an "International" category. In addition to 30 or so of the USA's top long range shooters, about 60 to 70 top long range shooters from around the world were also there to check out Sierra's prototype Palma bullet. We shot that load at 600, 800, 900 and 1000 yards over a five day period. Temperatures ranged from the 50's in early morning to the low 90's in mid afternoon. Each person fired 170 record shots. An Australian won the International Palma match aggregate fired at 800 through 1000 yards for each of 3 days. I won the International 600 and 1000 yard aggregates fired over 2 days. I also had the high combined International aggregate for all 5 days beating that Australian by only two points. I though that was a pretty good thing for both me and Sierra's then new Palma bullet.
I asked many top scoring shooters how that ammo shot at its worst in their rifles. They all said it did about 3 to 4 inches at 600 yards and about 7 to 8 inches at 1000 yards. All the folks from overseas said it was the most accurate ammo they had ever shot. Considering that all sorts of light to medium weight 30-inch barrel profiles and internal dimensions were used in temperatures ranging from the 50's to the 90's, that load had to do very, very well regardless of what barrel whip issues existed. The International Palma Committee met soon afterwards and decided that from then on, only the Sierra 155-gr. Palma bullet would be allowed in international matches.
And everybody at the 1992 World Championships loved that ammo. I didn't make the US team that year but one of their top shooters borrowed my rifle and did well with it.
When I got a new Palma rifle built in 1993, I loaded 22 rounds of that stuff but used WCC60 cases full-length sized to new case dimensions. Arriving at the local 1000-yard range about 5 AM one Tuesday morning, I put up a foam board target at 800 yards, laid down slung up prone and looked through the Weaver T20 scope I'd mounted on the rifle as I fired two shots to center my group on target. Then I fired 20 shots each about 30 seconds apart. A picture of that 3.2-inch group was sent to John Krieger (great barrel maker) and he used it in a 1997 issue of Precision Shooting magazine to advertise his great barrels.
When with the US team in South Africa in 1998 for their national matches, they had loaded Sierra 155's at some arsenal for us to use. We shot that stuff for over a week in our various whippy barrels. I came in second for one of the daily aggregates. It was as good as any "perfect" handload any of us had put together. In talking with several folks from around the world about their ammo some said it was as good as the stuff they shot in 1991 at Raton, NM.
Form any conclusions you want about the same load not performing well in a variety of barrels and atmospheric conditions. I'm just sharing some realities of what's possible for best accuracy. I can only conclude that each rifle must have had its bullets leave its barrel at close to the same point it its single whip and it didn't matter very much where that point was.
If both have the same bore, groove, twist and chamber dimensions as well as the same ammo used, I don't think there would be any difference in accuracy. People who have measured (not guessed) how a barrel whips vertically when fired know there is only one whip. It's much like the wave in a bull whip when it's flung out across a male bovine's backside. As long as the bullet leaves the barrel at about the same place in that single whip, it will go to the same small cluster of shots previously fired.
Lerch also says: "Not to mention that all of the benchrest shooters and extreme range enthusiasts shoot barrels that look like sewer pipes!!"
That's not quite true albeit a popular belief among rifle shooters. If one checks out the barrel dimensions of folks on Palma teams around the world as well as folks in the USA shooting prone rifles in 600 and 1000 yard matches, they'll learn those barrels are skinnier and more whippy than the 'sewer pipes' used in bench rest matches. Yet the accuracy they attain when fired under equal conditions are all equal.
Bill Bailey says: "I think the whole key here is CAN BE as accurate. With out a doubt there are skinny bbls out there that have shot some great groups. The problem is the load has to be precisely tuned to the bbl. The skinny bbl WILL NOT shoot as good, day in and day out under varying temps and atmospheric conditions using the same load. Could you tune the load for every condition? Sure you could, but who wants to have ump-teen different loads when you could just have a heavier bbl that will vibrate w/a much lower magnitude that will shoot the SAME LOAD into respectable groups under most all conditions. Now you still may have to have a summer and winter load, but 20-30 degrees won't make much difference."
The above is a very common (popular) belief. Consider what happened in 1991. The US Palma Team Captain asked in late 1990 if I and several other former Palma team members would help develop the ammo to be used for the 1992 World Long Range and Palma Championships. As this match was to be held at the NRA range at Raton, New Mexico, all the ammo had to be supplied by the USA; everybody would shoot the same stuff. The host country always supplies the ammo.
Our criteria was simple, use new .308 Win. cases, Federal 210M primers, metered (not weighed) powder charges of several powder makes and types, then seat Sierra Bullet's then a prototype .3084-in. diameter 155-gr. Palma bullet to an OAL of 2.80 inches. We all used various powders including RE15, AA2520, IMR4895, IMR4320, WW748 and a couple others I now forget. These loads were tested in several Palma rifles with different actions but all had 5- to 6-pound 30-inch barrels with tapers much like those I mentioned earlier about 1.2 inches at the back and about .800 at the muzzle. Bore diameters ranged from .2980- to .2995-in., groove diameters from .3065- to .3075-in. Mine was .2980 and .3070. Bullet runout on our development loads was mostly in the .001- to .003-in. range. We shot our ammo at 1000 yards with both aperture and scope sights. After each of us had shot a few 20-shot strings with each load, it was easy to tell which ones shot great and which ones didn't. The load selected was 45.3 grains of IMR4895.
Winchester said they would make the cases but our ammo master said he wanted to go to their plant and check tolerances before the production run was made for a few hundred thousand cases. The plant had to change their case forming dies and setup three or four times to get body and neck wall thickness tolerances down where we wanted them. But the results were worth it. Those cases were probably the most uniform made since the famous WCC58 and WCC60 stuff Western Cartridge Company made for the US Olympic Team's free rifles.
Two Dillon 1050 progressive machines made the ammo. One resized just the necks so bullet grip would be uniform and seated the 210M primers. The other 1050 metered powder and seated bullets. While our ammo man's two sons were busy cranking out ammo, he randomly grabbed 22 rounds one day then took them to his local 600 yard range to test them. He clamped his Winchester 70 Palma rifle in a machine rest, fired two shots to center the group on a target, then fired 20 consecutive shots in about 15 minutes. That 20-shot group was shown in a 1991 issue of Handloader Magazine; it measured about 2.7 inches between widest centers. Not too shabby for ammo with powder charges having a 3/10ths grain spread and bullet runout up to .004-in. And the first time that barrel had shot that ammo.
Samples of all our test loads were sent to a ballistics lab. The ammo with the lowest muzzle velocity spread, smallest charge weight spread and most uniform chamber pressures used AA2520 ball powder. That load was also the worst for accuracy in all the test rifles. Only average spreads in muzzle velocity, charge weight and peak pressure happened in the selected load using IMR4895. But it was the most accurate.
In the summer of 1991 at a big long range match at the NRA Whittington Center south of Raton, NM, several thousand rounds of that load were made available to rifle shooters to compete in an "International" category. In addition to 30 or so of the USA's top long range shooters, about 60 to 70 top long range shooters from around the world were also there to check out Sierra's prototype Palma bullet. We shot that load at 600, 800, 900 and 1000 yards over a five day period. Temperatures ranged from the 50's in early morning to the low 90's in mid afternoon. Each person fired 170 record shots. An Australian won the International Palma match aggregate fired at 800 through 1000 yards for each of 3 days. I won the International 600 and 1000 yard aggregates fired over 2 days. I also had the high combined International aggregate for all 5 days beating that Australian by only two points. I though that was a pretty good thing for both me and Sierra's then new Palma bullet.
I asked many top scoring shooters how that ammo shot at its worst in their rifles. They all said it did about 3 to 4 inches at 600 yards and about 7 to 8 inches at 1000 yards. All the folks from overseas said it was the most accurate ammo they had ever shot. Considering that all sorts of light to medium weight 30-inch barrel profiles and internal dimensions were used in temperatures ranging from the 50's to the 90's, that load had to do very, very well regardless of what barrel whip issues existed. The International Palma Committee met soon afterwards and decided that from then on, only the Sierra 155-gr. Palma bullet would be allowed in international matches.
And everybody at the 1992 World Championships loved that ammo. I didn't make the US team that year but one of their top shooters borrowed my rifle and did well with it.
When I got a new Palma rifle built in 1993, I loaded 22 rounds of that stuff but used WCC60 cases full-length sized to new case dimensions. Arriving at the local 1000-yard range about 5 AM one Tuesday morning, I put up a foam board target at 800 yards, laid down slung up prone and looked through the Weaver T20 scope I'd mounted on the rifle as I fired two shots to center my group on target. Then I fired 20 shots each about 30 seconds apart. A picture of that 3.2-inch group was sent to John Krieger (great barrel maker) and he used it in a 1997 issue of Precision Shooting magazine to advertise his great barrels.
When with the US team in South Africa in 1998 for their national matches, they had loaded Sierra 155's at some arsenal for us to use. We shot that stuff for over a week in our various whippy barrels. I came in second for one of the daily aggregates. It was as good as any "perfect" handload any of us had put together. In talking with several folks from around the world about their ammo some said it was as good as the stuff they shot in 1991 at Raton, NM.
Form any conclusions you want about the same load not performing well in a variety of barrels and atmospheric conditions. I'm just sharing some realities of what's possible for best accuracy. I can only conclude that each rifle must have had its bullets leave its barrel at close to the same point it its single whip and it didn't matter very much where that point was.
