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  #22  
Old 04-06-2013, 03:39 PM
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Join Date: Feb 2012
Location: South Louisiana
Posts: 27
Re: Need Help

Would I be correct if I were checking to see if my scope is tracking vertical I would shoot a shot at 100 yards add 27MOA shoot at 100 yards again, would that show if the bullet was tracking off vertical?
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  #23  
Old 04-06-2013, 04:48 PM
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Join Date: Jan 2013
Location: Meridian, Idaho
Posts: 1,116
Re: Need Help

You could for sure. You could do a box test as well.
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  #24  
Old 04-06-2013, 05:34 PM
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Join Date: Feb 2012
Location: South Louisiana
Posts: 27
Re: Need Help

Ok great I saw that on TV once.
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  #25  
Old 04-07-2013, 06:42 PM
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Join Date: Oct 2012
Location: Colorado
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Re: Need Help

Quote:
Originally Posted by lougonl View Post
Would I be correct if I were checking to see if my scope is tracking vertical I would shoot a shot at 100 yards add 27MOA shoot at 100 yards again, would that show if the bullet was tracking off vertical?
This should work really well. You should also be able to verify if the scope is tracking perfectly verticle as well (use a level to make sure that the vertical change is plumb). If your scope is not level, this would help show it.
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  #26  
Old 04-07-2013, 07:59 PM
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Join Date: May 2008
Location: South of Canada and North of Wyoming
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Re: Need Help

Quote:
Originally Posted by lougonl View Post
I have 2 long range rifles but will talk about one today. I am having problems with my ballistic solution I cannot get it to match up. I have shot my data and know what MOA is needed to hit zero and several distances but cannot get the balistic programs to match up with this data and I have tried a few programs. I will list the data I have if someone can please tell me what I am doing wrong, I am desperate. I am faily new at this.
308 WIN
168 Grain Berger Classic Hunter
BC G-1 .496 G7 .254
Muzzle Velocity 2553 FPS
Sight above bore 2"
Sighted in at 200 yards
Elevation 100'
Temp 65 degree's
Humidity 65%
400 5.5 MOA
500 8.75 MOA
600 14 MOA
700 20 MOA
800 27 MOA
Please help me!!!
I don't see where you mention Barometric Pressure? That will make a difference.

Things to check...
-Correct vertical alignment of your scope to your bore, I use a plum bob
-Actual scope tracking, you can check this by locking your rifle into a rifle vice at a range and checking the travel against a yard stick @ exactly 100 yds from the scope. 120 clicks (30 MOA) should equal 31.41"
-Accurate scope height.

Off the top of my head, the cause appears to be either a tracking problem or an incorrect BC or a combination of things. Your rate of ballistic decay is greater than the BC you're using suggesting the actual BC is lower. Velocity is always suspect.

In this case your actual drops vs charted drops are less @ 400 and 500, about the same @ 600 and lower @ 700 and 800.

This suggests to me that actual velocity is higher and actual BC lower than programmed.... assuming actual scope height, alignment, and tracking are correct.

Also need to know the Barometric Pressure.
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Last edited by MontanaRifleman; 04-07-2013 at 09:55 PM.
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  #27  
Old 04-07-2013, 09:45 PM
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Join Date: Feb 2013
Location: Central MT
Posts: 572
Re: Need Help

Lougonl,

Hope you are still hanging in there. I thought I would throw this up for you.

308 Drop Adjustment.pdf

This ballistics profile matches the majority of your drop MOAs but doesn't quite make much sense. There appears to be an error or multiple errors in your actual drop MOA correction or you have a variety of ranging errors needing confirmation. Here is a list of steps I take to help isolate ranging errors.

1. Confirm the range. Should be pretty easy if shooting on a range with known distances or verified with a rangefinder. I don't see this as being the problem
2. Apply muzzle velocity variation to the ballistics solution. Again, it will be helpful if you can confirm your velocities with a chronograph and provide your calculated ES and SD.
3. Confirm atmospheric conditions. Has your air density changed?
4. Confirm elevation turret correction settings. Is your scope tracking correctly and have you confirmed click values and verified your zero? Have you applied the corrected solution to your elevation turret? (The later will not apply in your situation with developing actual drop comparisons).
5. Is your ballistics solution validated? Have you used two sources to validate your ballistics solution? The solution above is not validated.

Hope this helps and take one bite at a time. Good luck and good shooting.
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  #28  
Old 04-08-2013, 05:11 AM
Junior Member
 
Join Date: Feb 2012
Location: South Louisiana
Posts: 27
Re: Need Help

Oh yea still hanging in there MMERSS.
I am starting my 7 days off tomorrow I will take these tip one at a time and start rulling things out. I want to thank everyone for the help. I will let you know how I come out.
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