Long Range Hunting Online Magazine


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


Reply

Help Needed with LB3.0 and .338 Bergers

 
LinkBack Thread Tools Display Modes
  #1  
Old 06-06-2010, 04:35 PM
Platinum Member
 
Join Date: Feb 2007
Location: Townsend, Montana.
Posts: 7,816
Help Needed with LB3.0 and .338 Bergers

Well if you guys that have LB3.0 figured out are not sick of me or mad at me yet, . I would like to ask for assistance. I feel, or, I hope, I have enough good solid data gathered to tune the curve in LB 3.0. I will give a summery of what has been done and rifle specs and see what you all think is needed to get my dial ups to match my drops.

Here we go.

Rifle is a .338 Lapua mag with 1 in 10 twist 27.5" tube.

Load is Lapua case, 91.5 gr of H-1000, CCI 250, .015" off the Lands.

Chrono was 2820 but I have found this chrono to be 30 fps fast when compared to others. So I feel 2790 MV is accurate.

ES is in single digits with 5 tested.

Sight in data:
MV 2790
BC .455 / G7
DC .500
Click setting .250
Sight Height 2.10
Zero Range 300 yds
zero height 0
incline 0

Zero was dead on 3 shots touching

700 yards test
FC= temp 68*
Baro=25.8
Alt= 3920
Overcast, light head wind 3 mph to 0
Group average was 2.5" low 10.5 moa up was used

1042 yard test
FC= temp 68*
Baro= 25.8
Alt= 3920
5 mph 12:00 head wind, light mirage, .25 moa added for headwind
Average group was 10" low 21.75 moa up was used

1342 yard test
FC= 68*
Baro= 25.68
Alt= 4054
Mirage increasing, overcast to sunny, 11:00 wind at 6 mph
Group average was 5" low 34.25 moa up was used.




I just shot these 3 test groups. The Bergers were holding .6 moa at 1342 and .5 moa or less at 1042 and 700.

I also have the windages used but would like to get the ups dialed in first.

I do appreciate any and all help. I really need this perfected to extend my effective range for hunting past 1150 yards.

Thank You!

Jeff
__________________
Reply With Quote
  #2  
Old 06-06-2010, 08:46 PM
Platinum Member
 
Join Date: Nov 2008
Location: SW Montana
Posts: 4,456
Re: Help Needed with LB3.0 and .338 Bergers

I've been able to get the numbers real close but I don't like what I have to do to get it.

I have a couple questions. Have you calibrated your Kestrel Baro/altitude? Have you check that the scope is moving true MOA?

One thing that would possibly work is to shoot over your chronograph at 4 different ranges and use the DC function in the Analyzer tab. That will give you a BC and drag that is specific to your set up.
__________________
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
  #3  
Old 06-06-2010, 09:14 PM
Platinum Member
 
Join Date: Feb 2007
Location: Townsend, Montana.
Posts: 7,816
Re: Help Needed with LB3.0 and .338 Bergers

Quote:
Originally Posted by bigngreen View Post
I've been able to get the numbers real close but I don't like what I have to do to get it.

I have a couple questions. Have you calibrated your Kestrel Baro/altitude? Have you check that the scope is moving true MOA?

One thing that would possibly work is to shoot over your chronograph at 4 different ranges and use the DC function in the Analyzer tab. That will give you a BC and drag that is specific to your set up.
I agree, you really have to stretch numbers to even get close.

Yes, durring this process I did re-calibrate my kestrel.

Yes, twice with 3 shot groups. I have checked the scope at 100 yards for moa / inches. zero , 10, 20, 25, 30, 35 moa. It is spot on to 20 some moa but adds a bit more than it should at 35 moa. But all in all is whith in .5 moa.

Which as you can see is just backwards to what the actual drops showed.

I could shoot more at a chrono at distances. But still we should be able to find those majic numbers for BC, DC and MV. By just adjusting it with the drops I shot today.... Correct?

I should also say. I was very good with the 300 SMK and a banded BC of .768 using exbal. My velocity was very close to what I chronod too. I shot this combo from 700 to 1400 yards regularly. I have also taken a yote at 880, a small deer at 1137 and an elk at 1130 all one shot kills with exbal and 300 SMK's. It was when I started using the new Bergers that I started having trouble. So I purchased LB3.0 and have been struggling since. Don't get me wrong, the Bergers have recorded steller groups. I am confident I can shoot very close to .5 moa to 1400. But just cant get the come up right.

Jeff
__________________

Last edited by Broz; 06-06-2010 at 09:17 PM.
Reply With Quote
  #4  
Old 06-06-2010, 10:02 PM
Platinum Member
 
Join Date: Nov 2008
Location: SW Montana
Posts: 4,456
Re: Help Needed with LB3.0 and .338 Bergers

That's kinda what I figured you would say hummmmm! The G1 Bc of .891 seems to be closer but still not within the range that we can just tweek the drag.

We could tweek the numbers to get it right but you don't really know what is the real culprit, using true numbers is the goal. Using the Analyzer BC function of Loadbase basically gives you the BC and drag of that bullet in that rifle.

Using a G1 BC of .800 and a .500 drag and all other numbers left alone I get seriously close.
__________________
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
  #5  
Old 06-06-2010, 11:23 PM
Platinum Member
 
Join Date: Feb 2007
Location: Townsend, Montana.
Posts: 7,816
Re: Help Needed with LB3.0 and .338 Bergers

After playing with the numbers here for quite a while. I have found that using a these numbers get very close. Close enough that I want to retest with them. Unless someone can see me headed in the wrong direction again.

MV=2780
G7 BC = .415
DC= 300

Wu chu tink?

Jeff

__________________

Last edited by Broz; 06-07-2010 at 08:06 AM.
Reply With Quote
  #6  
Old 06-07-2010, 12:06 AM
Platinum Member
 
Join Date: Nov 2008
Location: SW Montana
Posts: 4,456
Re: Help Needed with LB3.0 and .338 Bergers

You said you can get accurate drops for the 300gr Sierra from Exbal, have you tried it with LB to see if you can accurately predict the same drops as Exbal with the Sierra. That could shed a little light on the problem.

You could shoot with your latest numbers but I think I would find a way to at least run the BC test in the Analyzer as you only need two velocities over one range to get a G1-G8 BC. The DC function in the analyzer you have to shoot four ranges but it also gives you the BC and drag. If you do the BC test with a muzzle velocity and a velocity at your 300yrd sight in it may show you that your rifle is producing more drag, the farther you can shoot and get a reading the better the data will be.

If my back wasn't so tweeked I'd load up the crony and my steel plates and give you a hand!
__________________
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
  #7  
Old 06-07-2010, 04:47 AM
Platinum Member
 
Join Date: Feb 2005
Location: Nevada
Posts: 2,782
Re: Help Needed with LB3.0 and .338 Bergers



I will try to explain what I did; you got to promise me you won't shoot me! That's for you Jeff!




I asked my self, what are the positive things in this project? The answers came right along.
  • Broz is a great shot with good equipment
  • I have an awesome Ballistic Program to work with
  • Bryan Litz G7 BC are mighty trustable and...
  • I can pray to have the Lord help me.
Then I though, what are the things that are bothering me about this project... The answer jumped in front of me... MV!!!!! After looking at all the data and the different results I was convinced that something was very wrong and it had to be the muzzle velocity... no doubt!!!




****************************************

I gave load base the zero info and assumed the the conditions were the same as the first two set-ups at 700 yd and 1042 yards.


Note: LB3.0 uses angles for wind directions. 5 minutes is 30 or 2 O'clock is 60 11 O'Clock is 330. Personally I like the clocks better. Just keep this in mind.

For 700 yards, I used a 0 wind direction (12 O'clock) at 3.0 mph; LB3.0 says to go up 10.3 moa. Broz used 10.5 moa and was 2.5 inches low. So... 0.2 moa higher than what he needed means (0.2*1.047*7) = 1.47" It should have been 1.5 + 2.5 = 4.0" low. In all truthfulness Broz was 4.0" low at 700 yards. Now, 4" at 700 yards means (4/1.047/7) = 0.5 moa. Then 10.3 moa (the original drop) + 0.5 moa (the adjustment) would need a total of 10.8 moa to be right on target at 700 yards.

Great, I need to start dropping my MV until I get to need 10.8 moa and then compare it to the next two shooting settings and continue wit my adjustments. But before I started dropping the MV, I decided I needed to know what my come ups would have to be for 1042 yard and 1342 yards.

Let's do the next one...

With the exact same info in LB3.0 I changed the wind speed and direction to 5 mph at 0 again. LB.3.0 said I needed 21.1 moa to be on target. Broz used 21.75 moa; he used 0.65 moa more which means he should have hit 7.1" higher at 1042 yards. (0.65*1.047*10.42) = 7.09"

The center of his group was 10" low. Let's add 10 + 7.1 = 17.5" I would need to come up 1.6 moa more and that'd be a total of 22.7 moa at 1042 yards.

Now the last one...

I turned on the field conditions because the environment conditions changed. I keyed in the new conditions, entered the 330 for wind direction and 6 mph velocity.

LB3.0 said that I need 32.5 moa. Broz used 34.25 and was 5" low. Now he used 1.75 moa more than it called for to still be 5" low... So 1.75moa*1.047*13.42 = 24.6" at 1342 yards plus (+) 5" = 29.6" which is 29.6/1.047/13.42 = 2.1 moa. Now 2.1 moa + 32.5 = 34.6 moa for total corrected adjustment.

************************************************** ****'

AT this point I need to bring my MV down and play with BC and DC to be able to obtain as close as possible come ups the would look like so:

700 yards would have to say -10.8 moa

1042 yards would have to say -22.7 moa

1342 yards would have to say -34.6 moa

ARE YOU READY TO BE SHOCKED!!! HERE WE GO!!!!


When using the muzzle velocity of 2705 fps and without changing the G7 BC's value and setting the DC = 0.492 The following results are obtain:


If we had used the Coriolis effect it would probably be even more adequate.

Remember to change the wind direction and speed as well as turning on the field conditions for the last group at 1342 yards since the conditions were different.

Cant wait till you check it and let us know what it does.

The new muzzle velocity does make sense to me since you're using 91.5 grains of H1000 and you're barrel is 28.5 inches long.

In all my calculations there was an extra step that I did, I did not have to do it, just because I wanted to make sure that all was being referenced to LB3.0 original drop info.

Well I do hope this works!!!
__________________
-----------------------------

-----------------------------
HEBREWS 13:8
Jesus Christ the same yesterday, and to day, and for ever.

Our Lord Jesus said that as it was in the days of Noah and
also as it was in the days of Lot so it shall be in the days...
It's happening again!!! God sent to us His prophet, and His Word
to this generation and we once more are rejecting it as was prophesied!!!

---> As promised, God Sent His Prophet to us!

Last edited by Eaglet; 06-07-2010 at 10:41 AM.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: Help Needed with LB3.0 and .338 Bergers
Thread Thread Starter Forum Replies Last Post
WTB 338 300 gr Bergers or SMK Idaho Sawyer Reloading Equipment and Components 4 03-23-2011 08:15 AM
300 wsm & 190 bergers lineman69 Reloading 2 03-22-2011 04:31 PM
FS 30 cal. 168 VLD bergers Idaho Sawyer Reloading Equipment and Components 0 04-27-2010 07:16 PM
WTT: 168gr Bergers for 180gr Bergers longrange.270 Reloading Equipment and Components 0 07-31-2009 09:29 PM
338 Bergers hegster Rifles, Bullets, Barrels and Ballistics 1 01-28-2009 03:41 PM

Current Poll
Do you archery hunt for elk?
YES - 31.84%
64 Votes
NO - 52.24%
105 Votes
Not yet, but I plan to. - 15.92%
32 Votes
Total Votes: 201
You may not vote on this poll.

All times are GMT -5. The time now is 05:17 PM.


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