24hourcampfire.com
24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
Joined: May 2005
Posts: 1,525
C
Campfire Regular
OP Offline
Campfire Regular
C
Joined: May 2005
Posts: 1,525
Anyone?

HR IC

Joined: Sep 2007
Posts: 3,612
Campfire Tracker
Offline
Campfire Tracker
Joined: Sep 2007
Posts: 3,612
I thought they were a 1 in 9 like the Model 70 Winchester's


Gerry.
Joined: Apr 2011
Posts: 150,067
Campfire Savant
Online Content
Campfire Savant
Joined: Apr 2011
Posts: 150,067
1 in 9

Joined: May 2005
Posts: 1,525
C
Campfire Regular
OP Offline
Campfire Regular
C
Joined: May 2005
Posts: 1,525
Thank you

Joined: Nov 2009
Posts: 425
B
Campfire Member
Offline
Campfire Member
B
Joined: Nov 2009
Posts: 425
Yup, 1 in 9. My CDL .264 barrel is a tomato stake now... Keep thinking about having one built but it will be 1:8.

IC B2

Joined: Jul 2001
Posts: 59,898
M
Campfire Kahuna
Offline
Campfire Kahuna
M
Joined: Jul 2001
Posts: 59,898
Actually a 1-9 would work fine in western Colorado, just as well as a 1-8 a lower elevations.


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
Joined: Nov 2009
Posts: 425
B
Campfire Member
Offline
Campfire Member
B
Joined: Nov 2009
Posts: 425
The idea was for it to be a gun for Texas/Mexico/Arizona Whitetail and Coues so the elevation here (which is still only 4,500ft) wasn't a real factor and I don't imagine regretting a 1:8 if I get a choice.

I'm sure there is better terminology but when I finally had enough of my CDL the gunsmith showed me how far off the bore was from being in the center of the barrel at the crown then with a bore scope he showed me the marks from where the bit had "chattered" its way down the bore. Not Big Green's finest rifle but I still drool over a .264 Sendero II.

Joined: May 2005
Posts: 1,525
C
Campfire Regular
OP Offline
Campfire Regular
C
Joined: May 2005
Posts: 1,525
So the factory twist may not stabilize the Berger vlds?

Joined: Feb 2015
Posts: 98
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Feb 2015
Posts: 98
As long as your gun has a magnum bolt face, magazine and follower; my thought would be to rebarrel it to an 8 twist 26 Nosler. That would be a really go fast hunting gun.
Just a thought.


Presidents 100-'97
Distinguished Rifleman-'81
NRA Benefactor
Artillery lends dignity to what would otherwise be a vulgar brawl.
Joined: Feb 2009
Posts: 4,529
J
Campfire Tracker
Offline
Campfire Tracker
J
Joined: Feb 2009
Posts: 4,529
Originally Posted by Cntrmass
So the factory twist may not stabilize the Berger vlds?



I've had two, bone stock 700 .264 WMs and had no problems with the Berger 140s or Scenar 139s at sea level.

IC B3

Joined: Apr 2011
Posts: 150,067
Campfire Savant
Online Content
Campfire Savant
Joined: Apr 2011
Posts: 150,067
I shot the 140 VLDs in my pre 64 westerner. They shot fine.

Joined: Jul 2001
Posts: 59,898
M
Campfire Kahuna
Offline
Campfire Kahuna
M
Joined: Jul 2001
Posts: 59,898
A lot depends on temperature as well as elevation. In warmer weather (typical of Texas) a "slow" twist will stabilize bullets that the same twist won't in truly cold weather--a potential problem here in western Montana, though it's somewhat counteracted by the higher elevation.

The rule-of-thumb is that every 5000 feet of additional elevation acts about like a 1" faster twist. So if you have a 1-9 twist 6.5mm barrel and don't shoot at any lower than 4000 feet in elevation, it will stabilize even with 140 Berger VLD's even at -20 Fahrenheit. The stabilization won't be enough to optimize ballistic coefficient, but the bullets will remain point on and probably be pretty accurate.

The 4000 feet is my situation, by the way. The town we live in is at 3900 feet, right along the Missouri River in the bottom of the valley, so every place else around here is even higher, including the two ranges I shoot at. As a result a 1-9 twist works for any 6.5mm round with 140 VLD's.

Even at sea level a 1-9 should stabilize (but not optimize) a 140 VLD down to -20 degrees. The reason many prefer a 1-8 twist isn't because it won't keep a 140 VLD point-on, or prevent them from shooting accurately, is that BC isn't optimized until the Sg is 1.5 or more.

Sg is a number assigned to a bullet's stability in a certain twist and conditions, with 1.0 the minimum needed for stabilization. But BC will increase up to a 1.5 SG, which is why many prefer a 1-8 twist, not because a 1-9 twist won't stabilize long 140-grain bullets. But it will result in a 1.5 Sg at 7000 feet above sea level, at a typical fall hunting temperature of 35 degrees.

Bullet stabilization isn't a simple either/or situation. It's affected not just by rifling twist, but by temperature, elevation and whether or not you want the highest BC the bullet's capable of.


“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
Joined: May 2005
Posts: 1,525
C
Campfire Regular
OP Offline
Campfire Regular
C
Joined: May 2005
Posts: 1,525
Thanks, just wondering how the vlds will shoot.
I run 130 grain sciroccos now. The shoot pretty well.


Moderated by  RickBin 

Link Copied to Clipboard
YB23

Who's Online Now
648 members (1badf350, 09wingates, 2003and2013, 007FJ, 160user, 68 invisible), 2,655 guests, and 1,181 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums81
Topics1,187,603
Posts18,398,309
Members73,817
Most Online11,491
Jul 7th, 2023


 







Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2024 24hourcampfire.com, Inc. All Rights Reserved.
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.33 Page Time: 0.176s Queries: 14 (0.003s) Memory: 0.8479 MB (Peak: 0.9457 MB) Data Comp: Zlib Server Time: 2024-03-28 13:32:11 UTC
Valid HTML 5 and Valid CSS