Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Reloading

Reloading Techniques For Reloading


Reply

240g Sierra bullet in a 1-12 twist barrel

 
LinkBack Thread Tools Display Modes
  #1  
Old 08-20-2009, 09:59 AM
Silver Member
 
Join Date: Jan 2004
Location: Dallas, Texas
Posts: 164
240g Sierra bullet in a 1-12 twist barrel

I have a 30-338 lapua that I am working up a load using the 240G Sierra bullet. I have been using IMR7828 and am getting 2800 to 2850 FPS out of it but it is a good news bad news scenario the good news is its on the paper the bad news is its all over the paper. It probably has a 6" spread. The bullet also looks like it is either tumbling or wobbling as it does not cut a clean smooth round hole. My question is am I running this bullet through a barrel that is putting too much spin? What are thoughts to correct this.
I do not have the bullet right up in the lands and maybe that is part of the problem but my first thought was am I asking something out of the barrel its not designed to do.
All suggestions are greatly appreciated.
Thanks
__________________
Texas Dave
Reply With Quote
  #2  
Old 08-20-2009, 10:49 AM
Platinum Member
 
Join Date: Nov 2003
Location: Washington State
Posts: 2,454
Re: 240g Sierra bullet in a 1-12 twist barrel

I think that's too slow a twist. Sierra reccomends a 9 twist. I shoot a 300RUM with 10 twist at about 3k fps MV. Acc'd to Litz/Miller equations it has a stability factory of 1.62, so should be OK at this rate. I'm guessing a 12 twist is not going to stabilize it. You need a faster spin rate. Good luck.
__________________
In the beginning God created the heavens and the earth. Genesis 1:1

"And can the liberties of a nation be thought secure when we have removed their only firm basis, a conviction in the minds of the people that these liberties are the gift of God?" Thomas Jefferson - Notes on the State of Virginia

www.wildsidesystems.com - Shelter for Your WildSide - http://www.youtube.com/watch?v=tYwgo...&feature=g-upl
Reply With Quote
  #3  
Old 08-20-2009, 11:11 AM
Platinum Member
 
Join Date: Jan 2003
Location: The rifle range, or archery range or behind the computer in Alaska
Posts: 3,511
Re: 240g Sierra bullet in a 1-12 twist barrel

+1

Your stuck with no heavier than a 210. The 12x isnt optimum with the 210's but will work. 180-200's would be better for the 12x.
__________________
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
Reply With Quote
  #4  
Old 08-20-2009, 12:19 PM
Platinum Member
 
Join Date: Jun 2007
Location: Fredericksburg VA
Posts: 4,109
Re: 240g Sierra bullet in a 1-12 twist barrel

You are running too slow a twist first off as everyone has said.

However, with the 240 in a 30-338, you should have been able to be closer to 3000 fps also (if your barrel was at least 28") which would help in the stability area with the faster rpm

300 WSMs can easily run 210s in 1-11 and even shot sub 4" groups (at 1000) in 1-12s at close to 3000 fps so you are not far off.

You can easily run 210s or 220s with a 1-12 if you are closer to the 3000 fps, but I would go to H1000, MRP, MRP2 or Retumbo. MRP and MRP2 has shown an ability to be able to give more fps in the large cases.

BH
Reply With Quote
  #5  
Old 08-20-2009, 01:25 PM
Platinum Member
 
Join Date: Nov 2003
Location: Washington State
Posts: 2,454
Re: 240g Sierra bullet in a 1-12 twist barrel

Even with the higher RPM, he's just not going to stabilize that bullet in a 1:12. After reading Litz's book, it's much more clear that RPM increase helps stabilization, but very little--much less than I would've thought.

Basically, don't depend on an increase in RPM to stabilize your bullet.

I would think you'd be able to push that 240g faster than you are. Have you tried US869? I'm using 104.2 g (cool weather load) to push 'em just under 3K with a 26" barrel. Need another range session with good lighting conditions to confirm, but after treating with GunJuice, I seem to be getting about 50fps faster MV's.

Good luck,

Jon
__________________
In the beginning God created the heavens and the earth. Genesis 1:1

"And can the liberties of a nation be thought secure when we have removed their only firm basis, a conviction in the minds of the people that these liberties are the gift of God?" Thomas Jefferson - Notes on the State of Virginia

www.wildsidesystems.com - Shelter for Your WildSide - http://www.youtube.com/watch?v=tYwgo...&feature=g-upl
Reply With Quote
  #6  
Old 08-20-2009, 03:34 PM
Silver Member
 
Join Date: Jan 2004
Location: Dallas, Texas
Posts: 164
Re: 240g Sierra bullet in a 1-12 twist barrel

Thanks all for the replies. I have been shooting the 180's in it and they work great. I realized last time at the range it was a 12 twist so that was why I asked. Live and learn I guess. I think I can get the speed you guy's are speaking about but I wondered about stabilizing the bullet. I had thought about H50BMG powder too but the twist is still in the way.
Thanks
__________________
Texas Dave
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: 240g Sierra bullet in a 1-12 twist barrel
Thread Thread Starter Forum Replies Last Post
7mm rem mag, 24 inch barrel, 1-9.5 twist, What bullet? savage7mag Rifles, Bullets, Barrels and Ballistics 6 07-12-2011 09:03 PM
Bullet weight for barrel twist- 7mm CLICKBANGBANG Rifles, Bullets, Barrels and Ballistics 1 12-07-2010 12:49 PM
twist needed for .308" 240g SMK's?? cowboy717 Rifles, Bullets, Barrels and Ballistics 5 06-21-2008 11:05 PM
Barrel Twist vs. Bullet Weight Quick Karl Rifles, Bullets, Barrels and Ballistics 3 01-13-2007 02:33 PM
Barrel twist effect on bullet hjl Rifles, Bullets, Barrels and Ballistics 9 06-29-2006 03:07 PM

Current Poll
How Many Different Cartridges Do You Reload For?
ZERO, all factory ammo - 8.02%
352 Votes
1 - 2.78%
122 Votes
2 or 3 - 14.54%
638 Votes
4 or 5 - 20.35%
893 Votes
6 or 7 - 14.84%
651 Votes
8 or 9 - 8.66%
380 Votes
10 or more - 30.81%
1,352 Vote
Total Votes: 4,388
You may not vote on this poll.

All times are GMT -5. The time now is 02:40 PM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC