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Joined: Jul 2001
Posts: 60,149 Likes: 11
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,149 Likes: 11 |
Hondo,
You're welcome! However, perhaps it should be noted that I consider it my job to actually try stuff.
Berger sent me some of the 170s, and after using their rifling-twist program, I thought it was sure possible for the bullet to stabilize around here in a 1-10 twist. So Berger should get most of the credit.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Joined: Oct 2008
Posts: 7,263
Campfire Tracker
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Campfire Tracker
Joined: Oct 2008
Posts: 7,263 |
What is the maximum bullet weight (length) I can shoot in a 1-10 twist 280 AI? I will sort of run the Berger twist calculator in reverse but this isn't always the same as actual experience. Right now I put the cut off with the 168 ABLR and am fine with this, bullets heavier than that go to the 7RM.
Last edited by Tejano; 02/21/20.
"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli
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Joined: Jul 2001
Posts: 60,149 Likes: 11
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,149 Likes: 11 |
I would use the JBM twist-rate calculator with any plastic-tipped bullet.
The guy who developed the basic twist-rate formula for high-BC bullets, Don Miller, eventually found the additional length of plastic tips has very little effect, because they're so light. The Berger formula doesn't take this into account, but the JBM program does.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Joined: Mar 2003
Posts: 1,702
Campfire Regular
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Campfire Regular
Joined: Mar 2003
Posts: 1,702 |
Mule Deer,
I have also read somewhere that the long hollow tips of the VLD type bullets are not accounted for in the basic twist rate formula (similar to the length of the plastic tip). I think I saw a published paper along those lines. I don't remember the details but it also referenced the plastic tips being lighter and required a different formula. Curious of your thoughts on this?
Thanks
Lou
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Joined: Apr 2011
Posts: 151,726 Likes: 14
Campfire Savant
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Campfire Savant
Joined: Apr 2011
Posts: 151,726 Likes: 14 |
I haven’t read all of this, maybe someone has brought this up. I wonder what Jack O’ Connor’s comments would be on this subject???
If you took the 270, 280, and 30-06, loaded them with 150 grain bullets, shot a game animal, you couldn’t tell a lick of difference in all three.
Last edited by hanco; 02/21/20.
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Joined: Mar 2006
Posts: 14,516 Likes: 1
Campfire Outfitter
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Campfire Outfitter
Joined: Mar 2006
Posts: 14,516 Likes: 1 |
I would use the JBM twist-rate calculator with any plastic-tipped bullet.
The guy who developed the basic twist-rate formula for high-BC bullets, Don Miller, eventually found the additional length of plastic tips has very little effect, because they're so light. The Berger formula doesn't take this into account, but the JBM program does. And if you want to include the marginally-stability effect on BC that the Berger calculator reports, Bryan Litz has found that BC decreases by approximately 3% per 0.1 decrease in SG from 1.5 down to 1.0, where the bullet destabilizes completely.
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Joined: Jun 2010
Posts: 13,930
Campfire Outfitter
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Campfire Outfitter
Joined: Jun 2010
Posts: 13,930 |
I haven’t read all of this, maybe someone has brought this up. I wonder what Jack O’ Connor’s comments would be on this subject???
If you took the 270, 280, and 30-06, loaded them with 150 grain bullets, shot a game animal, you couldn’t tell a lick of difference in all three.
I can and have. Mainly because the 150 Core-Lokts for the 30-06 come apart and commonly deer drop at the shot whereas the 150 CL in the .270 is a much tougher bullet and stays together and plows through thereby making one follow a short blood trail to one's deer.
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