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Joined: Mar 2006
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Campfire Outfitter
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Food for thought......
In my 6x47 Lapua switch barrel, comparing the 70 grain BT load in the 14" twist, to the 105 Berger load in the 8" twist, they run neck & neck to 550 yards, before the Berger starts taking over.
What quantity are you comparing, aalf? Wind drift w/ 10mph wind, drop, etc?
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Joined: Dec 2007
Posts: 16,132
Campfire Ranger
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Campfire Ranger
Joined: Dec 2007
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Food for thought......
In my 6x47 Lapua switch barrel, comparing the 70 grain BT load in the 14" twist, to the 105 Berger load in the 8" twist, they run neck & neck to 550 yards, before the Berger starts taking over.
What quantity are you comparing, aalf? Wind drift w/ 10mph wind, drop, etc? Just drop...... Of course wind will favor the better BC sooner, but at what point does it not matter if the coyote is in overdrive heading for the next section..... 
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Joined: Dec 2006
Posts: 3,612
Campfire Tracker
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Campfire Tracker
Joined: Dec 2006
Posts: 3,612 |
Food for thought......
In my 6x47 Lapua switch barrel, comparing the 70 grain BT load in the 14" twist, to the 105 Berger load in the 8" twist, they run neck & neck to 550 yards, before the Berger starts taking over.
What quantity are you comparing, aalf? Wind drift w/ 10mph wind, drop, etc? Just drop...... Of course wind will favor the better BC sooner, but at what point does it not matter if the coyote is in overdrive heading for the next section..... Drop is largely irrelevant, its just math. Wind a lot more variable, and where those big, slippery bullets come into their own.
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Joined: Jul 2013
Posts: 9,189
Campfire Outfitter
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Campfire Outfitter
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Why would you limit yourself with a 14" twist? You might want to shoot a longer bullet some day.
Not being intentionally snarky, just don't understand the reasoning. My dad shot bench rest rifles at targets and varmints for many years toward the end of his life. He used 6mm rifles and small 6mm cartridges and 1:14 twist barrels, using bullets from 60-75 grains. Some guys just want to shoot the light bullets. If that's the case, a 14-twist is the best twist. He shot lots of .1's. Why would he do that?? Faster rotation causes greater precession and nutation when asymmetries exist in the bullet. This was especially important in decades passed, as bullets were not balanced as well as they are today. With the quality of today's bullets, the negative impact of faster twist on precision is not nearly as large as it used to be. Bullets still aren't perfect, so for BR purposes an excessively fast twist might be a hindrance, but for the rest of us there is no downside to a faster-than-needed rate of twist. You're right, of course, but that isn't what the OP asked. I answered his question, and then I answered the follow-up question as to why. You have told me why it doesn't matter so much, but the answer still is what the answer is. The best twist for those bullets in that caliber is 1:14. I don't know why people want to argue about this. "Yeah, there is a tested-and-endlessly-proven standard coming from benchrest shooters that is definitely the best for precision in those bullet weights, but you should get a faster twist, because bullets are generally better than they used to be."
I belong on eroding granite, among the pines.
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Joined: Mar 2006
Posts: 14,490
Campfire Outfitter
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Campfire Outfitter
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Why would you limit yourself with a 14" twist? You might want to shoot a longer bullet some day.
Not being intentionally snarky, just don't understand the reasoning. My dad shot bench rest rifles at targets and varmints for many years toward the end of his life. He used 6mm rifles and small 6mm cartridges and 1:14 twist barrels, using bullets from 60-75 grains. Some guys just want to shoot the light bullets. If that's the case, a 14-twist is the best twist. He shot lots of .1's. Why would he do that?? Faster rotation causes greater precession and nutation when asymmetries exist in the bullet. This was especially important in decades passed, as bullets were not balanced as well as they are today. With the quality of today's bullets, the negative impact of faster twist on precision is not nearly as large as it used to be. Bullets still aren't perfect, so for BR purposes an excessively fast twist might be a hindrance, but for the rest of us there is no downside to a faster-than-needed rate of twist. You're right, of course, but that isn't what the OP asked. I answered his question, and then I answered the follow-up question as to why. You have told me why it doesn't matter so much, but the answer still is what the answer is. The best twist for those bullets in that caliber is 1:14. I don't know why people want to argue about this. "Yeah, there is a tested-and-endlessly-proven standard coming from benchrest shooters that is definitely the best for precision in those bullet weights, but you should get a faster twist, because bullets are generally better than they used to be." Not trying to argue, and that's also not what I said. I said for us non-BR shooters there's no downside to a faster twist, meaning that a faster twist does not result in a meaningful decrease in precision with today's bullets, but it does increase the range of bullet options we can shoot from the rifle. Again, not trying to argue your point, just commenting on the fact that "over twisting" doesn't make as much difference in precision as it used to. This is a discussion board, after all.
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Joined: Mar 2006
Posts: 14,490
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2006
Posts: 14,490 |
Food for thought......
In my 6x47 Lapua switch barrel, comparing the 70 grain BT load in the 14" twist, to the 105 Berger load in the 8" twist, they run neck & neck to 550 yards, before the Berger starts taking over.
What quantity are you comparing, aalf? Wind drift w/ 10mph wind, drop, etc? Just drop...... Of course wind will favor the better BC sooner, but at what point does it not matter if the coyote is in overdrive heading for the next section..... Best to put him on the ground before overdrive kicks in...
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Joined: Jun 2009
Posts: 1,461
Campfire Regular
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Campfire Regular
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the benchresters use a 14 twist and the y shoot 65- 68 bullets out of a 6ppc.
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Joined: Oct 2019
Posts: 1,078
Campfire Regular
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Campfire Regular
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My first “custom” varmint rifle was a 12” twist Hart on a Rem700 action in 6mm Ackley. It shot 55BT’s into tiny tiny groups at nearly 4300fps. It shot 70BT and Sierra BK great as well. I started wanting to shoot deer with it but never could get a100gr bullet to shoot under about 2” at 100 yards. It also shot 85 bthp sierras really well also. I’ve since shot quite a few deer with it with 70BTs and it kills like lightning. But if I were to do it again I’d go with a 10” twist. That barrel is on its last leg and when it goes back for its next barrel it will be a 10” twist. Probably another Hart but perhaps a Krieger.
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