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# Trajectory Validation ??

#1
07-10-2009, 10:37 AM
 Bronze Member Join Date: Apr 2008 Location: Echo Bay, On Canada Posts: 39
Trajectory Validation ??

I'm hoping some of you math guys can help with this one, Late yesterday afternoon I went out to my shoooting spot with my chrony and the sky was a little overcast, 3 shots with my 300 RUM with a 240gr mk and 78.2 gr Rl-22 avg 2830 or so it says. i put that and atmos data into my exbal and got 39.50moa(548.4") up for a 1325 yard shot (about 1325). 1st and 2nd shot my spotter didnt see at all. so i dropped it right down to 30 moa(413.4") just to see where i was and that we seen it hit low. My spotter told me right where it hit so i just used 4 mil dots for a hold over. As i was getting real close i adjusted a bit so i was using 29.25 moa + 4 mils and i was right on the money making 5 hits. Now according to my calculations, 29.25 moa = 403.06'' and 4 mils = 190.8'' at that range. Add them together and thats 593.8'' or 43.00 moa. This confuses me because thats higher then the 39.5 that exbal gave me. So i'm not sure if my math or range is off or what but is some one could tell me what my velocity is or what should have been the correct elevation adjust ment that would hepl alot . thanks

#2
07-10-2009, 04:46 PM
 Gold Member Join Date: Oct 2003 Location: Lizton, IN Posts: 774
Re: Trajectory Validation ??

Assuming you entered the scope height and atmospheric data correctly, 3.5 MOA is a bit more error than I would expect out of exbal. Easiest explanation is something was not right with your velocity input -- I'd start by double-checking that.
#3
07-10-2009, 05:56 PM
 Platinum Member Join Date: Oct 2005 Location: Michigan Posts: 2,232
Re: Trajectory Validation ??

Have you verified the clicks on your scope?

Also, as was already mentioned (velocity and scope height are important).

Which cronograph are you using?

AJ
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#4
07-10-2009, 11:31 PM
 Platinum Member Join Date: May 2008 Location: South of Canada and North of Wyoming Posts: 6,068
Re: Trajectory Validation ??

Are you sure your input was good?

Scope hieght?

Velocity?

Have you verified that load and velocity more than once?

BC? Are you using an accurate BC? It (G1 BC) will change through differnt velocities.

What scope do you have? and....

Have you done a box test for reliable repeatability?

If you get it figured out let us know.

-MR
#5
07-11-2009, 08:19 AM
 Bronze Member Join Date: Jun 2009 Posts: 93
Re: Trajectory Validation ??

Quote:
 BC? Are you using an accurate BC? It (G1 BC) will change through different velocities.
Assuming everything else is accurate as stated above, check your data in another program such as LoadBase 2.0.

If you G1 BC is a good number, LoadBase will let you adjust a factor called Drag Coefficient (DC is independent of G1 BC). This will bring your data and MOA tables in line with your actual results.

Send me all your data and I will run it for you if you like.
#6
07-11-2009, 12:58 PM
 Bronze Member Join Date: Apr 2008 Location: Echo Bay, On Canada Posts: 39
Re: Trajectory Validation ??

i have never had a problem with imput before or my scope. i'm using a leupold mark 4 8.5-25x. i just knew my velocity was going to be off but on my exbal , you can only use the tradjectory validation out to 1000 yards. Anyway heres my setup: Rem 300 RUM, Leupold 8.5-25x, Sierra MK 240gr(B.C 711) + 78.2 gr RE-22 sight height 1.75", sight in @ 100y
#7
07-11-2009, 04:19 PM
 Bronze Member Join Date: Jun 2009 Posts: 93
Re: Trajectory Validation ??

I sent you a PM email.

Last edited by woolecox; 07-11-2009 at 05:23 PM.

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