Calculating range adjustment for ranges you have not shot?

[Bigeclipse]

All,

my back yard range goes to about 300 yards however o have one spot where I can shoot 600 yards now. This is ONLY 600 yards due to obstructions and rolling hills. I have used jbm ballistics to calculate estimates for blank range but never for actual dialing in. So my question is let's say you worked up a load andthe ballistics program says dial up 10moa for 600 yards but you find out you actually need to dial up 10.5 or 9.5 or some other number. How can you take that info and back calculate for 500 and 400 yards etc?

 

[Bravo 4]

If your zero is good and trust the BC enough, just use your ballistic app and adjust muzzle velocity to match your new drop data at 600. If things don't line up from there then you have some bad data input somewhere in the app.

 

[Bigeclipse]

If your zero is good and trust the BC enough, just use your ballistic app and adjust muzzle velocity to match your new drop data at 600. If things don't line up from there then you have some bad data input somewhere in the app.

Hmm ok I'm confused. For example I know my muzzle data is spot on cause I'm using magnetospeed but what if the bullet manufactures BC is slightly off which is causing a slight issue. How would you compensate for the other ranges without shooting them?

 

[JMW67]

are you sure all the other data is correct scope height temp angle altitude and so forth also what bullet are you shooting some are know to be off a little on b.c.

 

[Bigeclipse]

are you sure all the other data is correct scope height temp angle altitude and so forth also what bullet are you shooting some are know to be off a little on b.c.

Maybe I'm Confusing people. I haven't shot the 600 yards yet. I was curious that since I can only shoot to 300 and then 600...if 600 is slightly off how can I feel confident about drops at 500 and 400 should I go hunting at the ranges without actually shooting those ranges. So let's say jbm states 10moa adjustment. I shoot at 600 and see I need a bit more like maybe 10.3moa. How do I know what 50 would now be?

 

[JMW67]

you are worried about a problem that does not exist yet shoot it and find out and then corrections can me made so it will work out

 

[Bigeclipse]

you are worried about a problem that does not exist yet shoot it and find out and then corrections can me made so it will work out

I understand. I was just trying to learn.

 

[JMW67]

after you try it get back with us it is an easy fix

 

[Canhunter35]

Hmm ok I'm confused. For example I know my muzzle data is spot on cause I'm using magnetospeed but what if the bullet manufactures BC is slightly off which is causing a slight issue. How would you compensate for the other ranges without shooting them?

It's hard to calculate bc from drops at only 600. Out past 800 you can start calculating your bc better but start with your mv, as long as your environmental inputs are correct and zero is good.

Your bc only needs to be close for 600 and under.

 

[dfanonymous]

Hmm ok I'm confused. For example I know my muzzle data is spot on cause I'm using magnetospeed but what if the bullet manufactures BC is slightly off which is causing a slight issue. How would you compensate for the other ranges without shooting them?

Doesn't matter. The bullet doesn't lie, so if you are trying to true .5 moa into your solution you need to bend those MV numbers inside transonic to match your known drop. I'm concerned that you are to roughly estimating the distance, make sure you have a laser'd distance to the target.
Using exact numbers makes it easier to align the software. Later if you were to shoot subsonic, usually there is some fine tuning then you're good until you bore or powder lot changes.

 

[Plinker147]

Once you shoot 600 and say your 8 inches high. Go to one of the apps like g seven and you can plug in you inches off at 600 in the validation line. Calculate the program and it will adjust your FPS to what MOA you need for 600. I've done it a lot and it has lined up at other distances. Shorter distance always line up. I have had further distances that didn't but that was a wrong BC issue

 

[sea2summit]

Hmm ok I'm confused. For example I know my muzzle data is spot on cause I'm using magnetospeed but what if the bullet manufactures BC is slightly off which is causing a slight issue. How would you compensate for the other ranges without shooting them?

So you're willing to bet your single measuring device is more accurate that the manufacturers stated BC? Interesting approach.

I'd just adjust the velocity. Or try both and see what gets you closest at your 300 and in targets. I'm betting one will have a measurable improvement over the other.

 

[Bigeclipse]

So you're willing to bet your single measuring device is more accurate that the manufacturers stated BC? Interesting approach.

I'd just adjust the velocity. Or try both and see what gets you closest at your 300 and in targets. I'm betting one will have a measurable improvement over the other.

Not single. Confirmed with one other magneto speed and a lab radar so I have pretty good confidence on the velocities.

 

[308win]

Elevation correction factor, look it up