Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels & Ballistics

Rifles, Bullets, Barrels & Ballistics Applied Ballistics


Reply

CEB 140grn G10 MTH & 6.5 WSM-

 
LinkBack Thread Tools Display Modes
  #50  
Old 07-12-2013, 02:17 PM
Platinum Member
 
Join Date: May 2008
Location: South of Canada and North of Wyoming
Posts: 5,953
Re: CEB 140grn G10 MTH & 6.5 WSM-

If a bullet starts to tumble, that will impede it's ability to open, especially non-tipped bullets.

What we have here is a test of a bullet from an 8 twist barrel which the makers recommend a 7 twist for. We knew this going into it to see if they might work in an 8 twist at higher altitudes and velocities.

It would be interesting to see the 2x6 exit hole.

More tests to come.
__________________
- Mark

You will never know how much it has cost my generation to preserve your freedom. I hope you make good use of it.
~ John Quincy Adams
Reply With Quote
  #51  
Old 07-12-2013, 02:46 PM
Platinum Member
 
Join Date: Feb 2010
Location: Gillette, WY
Posts: 2,756
Re: CEB 140grn G10 MTH & 6.5 WSM-

Jeff you make valid points,

All bullet manufacturers experience failures & never has there been a 100% conclusive determination stemming from a single test.

I'm just not that quick to turn up my nose I guess. This is the exact type of testing we need to share with the manufacturer if we want to see an improved product.

I do understand the fact that there was no expansion for one bullet encountering two different test mediums, that is most definitely cause for concern. I guess that makes two failures (one bullet) for one test. definitely a two'fer

It looks as though there could be an issue here, it's not the end of the world & I guarantee I won't stop using the 130's due to this. I will share this info with Dan (CEB Pres) in hopes of helping to improve their product.

I do wonder if a faster twist can have any effect in this situation. I can't say, sure couldn't hurt.


t
__________________
"I, however, view ethics as an individual decision. My ethics are mine - and I won't explain or justify them to anyone else. I seek nobody's approval, just that of my own conscience. "

Reply With Quote
  #52  
Old 07-12-2013, 03:38 PM
Silver Member
 
Join Date: Sep 2011
Location: Germany
Posts: 127
Re: CEB 140grn G10 MTH & 6.5 WSM-

Quote:
Originally Posted by MontanaRifleman View Post
I would say the 140's are on the edge of stability from a 1:8 twist barrel and at long range don't maintain terminal stability.
Stability increases with range.
Bullet rotation decreases much slower than velocity. With decreasing velocity yawing and pitching motions induced by imperfections in the bullets symmetry decrease also.
A bullet that is marginaly stable at short range will be more stable at long range than any of your stable hunting loads at 100yard.
Reply With Quote
  #53  
Old 07-12-2013, 04:55 PM
Platinum Member
 
Join Date: May 2008
Location: South of Canada and North of Wyoming
Posts: 5,953
Re: CEB 140grn G10 MTH & 6.5 WSM-

Quote:
Originally Posted by Beng View Post
Stability increases with range.
Bullet rotation decreases much slower than velocity. With decreasing velocity yawing and pitching motions induced by imperfections in the bullets symmetry decrease also.
A bullet that is marginaly stable at short range will be more stable at long range than any of your stable hunting loads at 100yard.
Greater stability factor is required for terminal performance (hunting) verses paper punching. A bullet that is stable in flight may not be stable once it encounters flesh, bone, wood, dirt, water, etc.

Also, another member recently tested the CE 308 200 gr bullets in his RUM. They stabilized @ 200 -300 yds and lost stability around 500 as I recall.
__________________
- Mark

You will never know how much it has cost my generation to preserve your freedom. I hope you make good use of it.
~ John Quincy Adams
Reply With Quote
  #54  
Old 07-12-2013, 05:29 PM
Silver Member
 
Join Date: Sep 2011
Location: Germany
Posts: 127
Re: CEB 140grn G10 MTH & 6.5 WSM-

Quote:
They stabilized @ 200 -300 yds and lost stability around 500 as I recall.
Thats dynamical stability failing, not gyroscopical as implied by twist rate.

Quote:
Greater stability factor is required for terminal performance (hunting) verses paper punching. A bullet that is stable in flight may not be stable once it encounters flesh, bone, wood, dirt, water, etc.
Right but again gyroscopical stability will be fine at long range or the bullets will show signs of keyholing at short range.
Reply With Quote
  #55  
Old 07-13-2013, 12:53 AM
Platinum Member
 
Join Date: Nov 2008
Location: SW Montana
Posts: 4,549
Re: CEB 140grn G10 MTH & 6.5 WSM-

Quote:
Originally Posted by Outlaw6.0 View Post
Jeff you make valid points,

All bullet manufacturers experience failures & never has there been a 100% conclusive determination stemming from a single test.

I'm just not that quick to turn up my nose I guess. This is the exact type of testing we need to share with the manufacturer if we want to see an improved product.

I do understand the fact that there was no expansion for one bullet encountering two different test mediums, that is most definitely cause for concern. I guess that makes two failures (one bullet) for one test. definitely a two'fer

It looks as though there could be an issue here, it's not the end of the world & I guarantee I won't stop using the 130's due to this. I will share this info with Dan (CEB Pres) in hopes of helping to improve their product.

I do wonder if a faster twist can have any effect in this situation. I can't say, sure couldn't hurt.


t
I would not take what I posted as proof positive because of the small sample size, heck I don't and I shot them into the berm! Nor would I say that you should stop shooting them, they are a dang good bullet but not up to the task I'm asking them to do, I do feel that if I can get one into a jug of water and let the nose experience hydraulic action it may open, unlike cup and core bullets mashing the nose over does not expose softer bullet so it really needs to open from and undamaged tip. I'm not writing them of entirely for sure, just for the intended purpose of this particular rifle which is being capable of doing an elk dirty at a grand with a 6.5

I hit the 2x6 three times and only found one bullet in the berm, all had clean holes like a drill through them, these bullets are stable without a doubt since I'm running a 1.6 stability factor. At my elevation I can easily run one inch less twist and be good and stable and I have had 100% straight clean holes at every range I've shot them. The bending comes because they are trying and usually successfully to porpoise up out of the dirt because they are not open, much like we find at 2000 yards with a 300gr SMK, every bullet will do it eventually at some range and speed.

I don't know what would help this bullet open better at range other than a tip, the copper is very soft so I don't think annealing would help like it did with the Matrix, a larger hole would help but that's not conducive to BC. I may be that just adding frontal area as in going to a 338 cal would be it and the 6.5 just won't make it that far, I have a 338 and some CEB's
__________________
High Fence, Low Fence, Stuck in the Fence, if I can Tag it and Eat it, it's Hunting!

"Pain is weakness leaving your body"
Reply With Quote
  #56  
Old 07-14-2013, 11:39 PM
Platinum Member
 
Join Date: May 2008
Location: South of Canada and North of Wyoming
Posts: 5,953
Re: CEB 140grn G10 MTH & 6.5 WSM-

Rhian,

That is interesting that the CEB's penetrated the 2x6 leaving perfect holes. One would think they would have begun to open, but them again, Berger advertises their bullets don't begin expansion until about 2-3" - but then again one would think they would expand in the dirt.

On stabilization, if you used the Berger calculator to determine your SF, your probably a little high. The CEB's have a lesser specific gravity then the Bergers and will have a lesser SF for the same inputs. I'm guessing your actual SF might be about 1.4, which puts it right on the border line for terminal stability. They may have had enough stability to penetrate the 2x and started tumbling afterward. This is all speculation of course but I think it's reasonable speculation and could be close to reality.

I'm also interested in how you calculated your terminal velocity. Is there a chance the actual velocity was a little lower? I'm actually not surprised if they aren't opening @1900 fps bieng a monolithic cunstruction with such a small meplat. I know Gerard Schultz was adamant about having a larger meplat for terminal performance and comparing his 308 177's, they are definitely larger than the CEB's and he advertises 1600 fps opening velocity, but as you said, that's not good for BC.

For a greater perspective, Joel Russo reported that he and some assosiates had "killed a bunch of elk at 500-1300 yds" with the 338 300 gr bullets in the initial testing of those. I wonder what his terminal velocities were at 1200-1300 yds? Maybe he can chime in if he reads this. I wonder if larger bullets with greater momentum facilitate opening at lower velocities better than the smaller bullets?

Cutting Edge Bullets terminal performance

Thanks again for your report and pics, I found them very informative and useful.

Hopefully I can add to it with some more results and data. I would like to compare the results with the 130's vs the 140's in stability and terminal performance out of an 8 twist at higher altitudes.
__________________
- Mark

You will never know how much it has cost my generation to preserve your freedom. I hope you make good use of it.
~ John Quincy Adams
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes



All times are GMT -5. The time now is 09:08 AM.


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