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Bullet drop compensation dials (BDC dials)

 
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  #15  
Old 05-09-2006, 08:14 AM
 
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Re: Bullet drop compensation dials (BDC dials)

NO!If you shoot at long ranges in excess of 600 yds the comeups in inches falls flat on its face at a thousand yards the inch calibration of turrets are off by several moa's. I do use Leuopold scopes that I have checked for accuracy of bullet impact per click of adjustement.
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  #16  
Old 05-09-2006, 08:36 AM
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Re: Bullet drop compensation dials (BDC dials)

[ QUOTE ]
NO!If you shoot at long ranges in excess of 600 yds the comeups in inches falls flat on its face at a thousand yards the inch calibration of turrets are off by several moa's. I do use Leuopold scopes that I have checked for accuracy of bullet impact per click of adjustement.

[/ QUOTE ]I guess I don't understand what you're talking about.

I've never seen a scope (or aperture sights, for that matter) whose adjustment knobs (turrets) are marked in inches. I don't even know of a scope maker who says their adjustments are marked in inches except to say they move impact a given amount for a given range but at any other range, they move more or less inches (or fractions thereof) per click. So I don't understand why you think they're marked in inches.

I've done a lot of shooting at 600 through 1000 yards with scopes. Never had a problem with their adjustments marked in MOA values.
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  #17  
Old 05-09-2006, 10:13 AM
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Re: Bullet drop compensation dials (BDC dials)

Bart this is what Old Bear is getting at. If you run a program like Exbal or Sierra there are differances between the MOA and the bullet path or trajectory in inches. They do not match when you are useing a scope that tracks in 1" per min., 1/4" per click increments. Just for an example, a chart printed out on exbal for 25-06 ackly shows 14.75 MOA at 1000 yards. The trajectory or bullet path column shows 154.6" of drop. To find the true (inches) MOA so it matches the scope you take the bullet path in inches and divide by the inches per click at 1000 yrds (154.6 div. by 2.5 = 61.84 clicks) now divide that number by FOUR to get your scopes MOA which is 15.46 in this case. Now go back and look at the MOA column on the same chart and it says you need to come up 14.75 MOA to hit your target. Thats 7.5 inches diference on a flat shooting gun. If you take the 14.75 MOA figure and times it by 1.0472 it comes out at 15.446 MOA which shows that they are stll useing 1.0472 on their calculations while most scopes are in 1 inch moa. Sierras program is the same. If you want to make the proper turret corrections you better be using some math unless you are shooting with a scope that is in true 1.0472 MOA. Depending on the gun the corrections at 1k can be 3/4 to 1 1/4 Min.-----7mmRHB
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  #18  
Old 05-09-2006, 10:27 AM
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Re: Bullet drop compensation dials (BDC dials)

I always hang a grid on the target board at 100yds (32"s long)to make sure the turrets are correct and repeatable.
--7mmRHB
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  #19  
Old 05-09-2006, 12:31 PM
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Re: Bullet drop compensation dials (BDC dials)

[ QUOTE ]
If you live at say sea level and your bdc is calculated for this alltitude and you book a Deer hunt in another state and the elevation of your hunt is 7500 feet,the difference in correction will be considerable....How do you account for this difference with a bdc?

[/ QUOTE ]
You print a new one. Man, you guys are all over Buffalobob's case like you didn't read what he said. Of course it isn't as accurate as carrying a computer with you in the field--which you ought to for extreme ranges--and nobody has ever said that it was.

But unless you are carrying a computer with you, there's zero difference in accuracy between a BDC and a pre-made drop chart you tape to your stock. They contain exactly the same information. I wouldn't use a pre-made drop chart for 1500 yd shots from a bench with a 60lb gun either...but not everybody here is doing that.
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  #20  
Old 05-09-2006, 02:41 PM
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Re: Bullet drop compensation dials (BDC dials)

Jon A

Thanks. I don't argue with people on the forum. I just say what I have to say and go on. I have built and used BDCs. People who haven't can say whatever they want to say.

BDC is an old technology, it works.

All that said I have three scopes with target turrets.

I didn't really realize anyone was giving me a bad time. People like to bash BDCs and Weatherbys a lot. It seems to pass for entertainment here. Other days people discuss whether one should shoot game animals with Sierra Match Kings. Then if that gets boring just say "Schmidt and Bender" real loud.

Have a nice day
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  #21  
Old 05-10-2006, 05:48 AM
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Re: Bullet drop compensation dials (BDC dials)

[ QUOTE ]
[ QUOTE ]
If you live at say sea level and your bdc is calculated for this alltitude and you book a Deer hunt in another state and the elevation of your hunt is 7500 feet,the difference in correction will be considerable....How do you account for this difference with a bdc?

[/ QUOTE ]
You print a new one. Man, you guys are all over Buffalobob's case like you didn't read what he said. Of course it isn't as accurate as carrying a computer with you in the field--which you ought to for extreme ranges--and nobody has ever said that it was.

But unless you are carrying a computer with you, there's zero difference in accuracy between a BDC and a pre-made drop chart you tape to your stock. They contain exactly the same information. I wouldn't use a pre-made drop chart for 1500 yd shots from a bench with a 60lb gun either...but not everybody here is doing that.

[/ QUOTE ]
First off my post was not in reply to bob's.
Secound in my opion you are talking talking about a drop table for each condition taped to target turrets,that is writen in yardage, I don't think that is the same thing as a BDC.As I undrstand BDc they have a cam set for a specific load at a specific altitude and distance.If you are printing a label apparrently you are tapeing them to target turrets.
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