dont know what to do

[doublebull]

I went shooting today to practice for my first 1000 yard shoot I shoot a 6.5 284 that i built its got a 28 inch barrel with the ratchet 4 riflings in it i shoot 140 gr berger and have a ballistics program on my i pod i shot at 220 yards without making adjustments it was 2.5 inches low then i shot it out at 420 yards and was 21 inches low then went to 600 and i had to dial up 9 moas i put that in my program and it said i had a bc of 1.75 i shoot 2970 fps just was wondering if someone had any ideas. im lost i was also shooting at 3270 feet elev. every thing matches for that bc

 

[retiredcpo]

Are you sure about your FPS Did you chrono the loads at around the same temp/alt?

 

[doublebull]

ya i ckecked it through two diff cornys

 

[trebark]

I went shooting today to practice for my first 1000 yard shoot I shoot a 6.5 284 that i built its got a 28 inch barrel with the ratchet 4 riflings in it i shoot 140 gr berger and have a ballistics program on my i pod i shot at 220 yards without making adjustments it was 2.5 inches low then i shot it out at 420 yards and was 21 inches low then went to 600 and i had to dial up 9 moas i put that in my program and it said i had a bc of 1.75 i shoot 2970 fps just was wondering if someone had any ideas. im lost i was also shooting at 3270 feet elev. every thing matches for that bc

Your ballistic program should have a basic set of information to input, then it will give you a drop chart that should be relatively close to reality.

If you can provide some more details, I am glad to run the numbers in Exbal and post the drop chart that it produces. Here's what we have and need....

Bullet: 140grain Berger VLD (or is it the Long Range hollow-point boattail?)
BC: .612 for the VLD (the LRHPB is .618)
Muzzle Velocity: 2970
Elevation: 3270
Site-in Temperature: ??
Scope Height (distance from center of bore to center of scope): ??
Site-in Distance: 100yards?

 

[doublebull]

it is 1.5 in scope hight 50 deg its the vld i ran the bc .612 and it said 10.9 moa but the moa i used to be on target was 9 moa and i produced a 3 inch group at 600

 

[rscott5028]

You were 2.5 low at 220. So, I re-ran your numbers with a 220yd zero using NF Bal.

@ 420yds, it shows you would have a 19" drop. Then, you would add another 2.5" because you weren't exactly zeroed at 220. Hence, you should've been 19+2.5=21.5" which is close to the 21" you stated.

@ 600yds, it shows you would have a 56.5" drop or ~9 MOA elev adj. Then, you would add another 2.5" because you weren't exactly zeroed at 220. Hence, you should've been 56.5+2.5=58" which is still close to the 9 MOA you stated.

@ 1000yds, it shows you will have a 231.1" drop or ~22 MOA elev adj. That should leave you about 2.5 low.

That's not the most scientific method. But, it should get you on paper or steel.

How many rounds have you chronied and how consistent is your MV?
That will be a big factor.

Good luck!
Richard

 

[retiredcpo]

I entered your info into my program and got
36 clicks to get to 600 yards or 9MOA

700=48 clicks(12 MOA)
750=54 clicks(13.5 MOA)
800=60 clicks(15MOA)
850=67 clicks(16.73 MOA)
900=74 clicks(18.5 MOA)
950=81 clicks(20.25MOA)
1000=88 clicks(22 MOA)

 

[doublebull]

my program you put in your zero range then the target range and then you put in how many inches low you are and when i did that it said it was a to high of a bc so i did it manually untill all three ranges that i shot were the same i dont know i have to work all week then on fri we sight are guns in just would like to know so i dont look dumb dont know what bc to go with

 

[trebark]

Dropped all your data into Exbal and here is the resulting table.

It would not be surprising that your actual adjustments might differ slightly. Exbal has a trajectory validation function where you can input the variances and it will automatically adjust. You might want to see if your program has such a function.

 

[rscott5028]

doublebull,

I like to establish a good/known zero and set my turrets to match.

From the info you provided, it looks like your zero is around 155yds.

But, perhaps I didn't understand all the info you provided.

Trebark's table shows you -4.3" at 225 yds. But, you seriously outperformed that with -2.5". So, you do not have a 100 or 200yd zero. Or, you changed your shooting position or technique between sessions.

If you can establish a solid 100yd zero, or zero your turrets with your POI 4.3" low at 225yds, his table will be very close.

In any case, I seriously doubt that the published BC for the Berger 140 is incorrect. They take that stuff very seriously.

It's far more likely that some other input is off a bit.

-- richard

 

[backwoods83]

I shoot 6.5x284 in 1000yrd ibs you will need 24.5-26moa depending on conditions, I use 139 lapuas at 3020 .617bc @1750ft and I usually settle around 25 3/8 moa. Good luck!

 

[doublebull]

well i went out and shot my gun at 1000 for sight in and it was 19 moa i still dont know whats going on but i shot good

 

[backwoods83]

You must be shooting in some thin air, like 6000ft DA that's pretty impressive.

 

[doublebull]

well it was raining to day so would that be thick air? I dont know im stunned about it and i shot a hundred yards to make sure it was zeroed