ballistic chart

[ebert]

is there a chart telling the different moa sight adjustments at different ranges from 100 to 1000 yards

[hiram]

for one thing, it depends upon distance between front and rear sights

[Dragoon 45]

Check out Mike Ventrino's and Steve Garbe's "SPG Handbook". There are charts in the back of it that give bullet drop for each cartridge by common bullet weights and velocities. The drop is in inches. If I remember correctly there is also a formula there that lets you calculate rough sight adjustments in 1/1000's of inches for the given distance. It will not be exact but will give you a good starting place.

[Don McDowell]

No there really isn't.
You can get some pretty close guess info by going to Hornady's web and using their ballistics calculator and then comparing those numbers to what you have noted on your rifle at the ranges available to you.
If you have say a 200 yd zero, a good place to start is add about 17 minutes for every 100 beyond, but that'll only get you close you'll have to confirm those numbers by the actual firing.
Then make careful notes and be sure and note the weather conditions, because a change in wind/light/temp or humidity can change the settings as much as 10 minutes.

[ebert]

i have a 45/70 shooting a 531 postell at 1150fps i am zeroed at 100 yds. my barrel is 34 inches how many inches of elevation do i need to shoot at 200, 300, etc. rough estimate. i don't want to burn up a lot of ammo hitting the ground. thankyou

[Don McDowell]

You're going to burn up ammunition hitting the ground whether you like it or not, that's just the way it works,right up until the time you've spent enough time shooting to get zeros' marked down in your log book at the various ranges..
As has been mentioned already you're going to need to come up 17 minutes minimum for each 100 yds past your last confirmed zero.

[Boz330]

i have a 45/70 shooting a 531 postell at 1150fps i am zeroed at 100 yds. my barrel is 34 inches how many inches of elevation do i need to shoot at 200, 300, etc. rough estimate. i don't want to burn up a lot of ammo hitting the ground. thankyou

Ebert, Don is right on, if you come up 34 MOA you should be pretty close. If you have a sight that is not in MOA then you are just going to have to slug it out till you get a zero at the required distances.
I just went through this with a 38-55 2 weeks ago. I had a zero for 100yd and I came up 33 MOA and I was on target at 300 but about a foot high. The boolit was a scaled down copy of the Postel but it was going a little faster than yours and I was shooting a shorter barrel.
If you are not sure how to read a Vernier sight try this site;
http://www.uslink.net/~tom1/vernier.htm

Bob

[SharpsShooter]

Paul Matthews presented a mathematical method to calculate the elevation changes in minutes of angle converted to vernier. Dragoon mentioned it is in Venturino's book. I'll see if I can find it for you. As has been said, it will be ballpark but the best way is through trigger time.


SS

[Tom Myers]

i have a 45/70 shooting a 531 postell at 1150fps i am zeroed at 100 yds. my barrel is 34 inches how many inches of elevation do i need to shoot at 200, 300, etc. rough estimate. i don't want to burn up a lot of ammo hitting the ground. thankyou

If your bullet is stable all the way out to 1000 yards, these sight settings should be quite close and get you on target.

The chart may be a bit optimistic as it is based on the calculated ballistic coefficient of 0.397 of a perfectly stable Postell bullet. In the real world, this doesn't happen too often.

The second chart indicates sight settings with a Postell bullet having a Ballistic Coefficient of 0.350.

No matter how much or how accurately you calculate, in the end it all comes down to trigger time in all kinds of conditions.

Hope this helps.


http://www.tmtpages.com/LinkSkyImages/forum_images/45-70/Postell%20Sight%20settings.gif

http://www.tmtpages.com/LinkSkyImages/forum_images/45-70/Postell%20Sight%20settings%20%23%202.gif

Reading a Vernier Sight (http://www.uslink.net/~tom1/vernier.htm)

[Don McDowell]

Depends on his front sight height, if its flat on the barrel it'll be fairly close, if its one of the taller front globes, gonna be plowing alot of dirt. Need a good spotter with a good scope with a pretty broad field of view.

[semtav]

Just got my load for my 45-90 dialed in at 100 yds and will check these as I move out 100 yds at a time. I'm using a 535 gr Money bullet, so it may be a tad different.
thanks tom


Brian

[montana_charlie]

Let's say your 'dialed in' hundred yard zero happens when the tang sight is set at 21 points.
And, let's say that 32 points gets you zero'd at 200 yards.
The difference (you can call it the 'delta') is 11 points.

For 300 yards, you can figure it will need '11 points plus 1' added to the 200 yard setting.
That would be 44 points, and the 'new delta' has become 12 points.

'New delta' plus 12 plus 1 (57 points), should be real close for 400 yards, and the new delta has changed to (12+1) 13 points.

Keep adding the 'new delta plus 1' for each hundred yard increase.

The numbers work for you have because that first 'delta' was established with your barrel length, shooting your load, with your bullet...all fired with the sight height of your sights.

To work in my gun, I would have to establish that 100/200 yard difference using my own stuff.

This won't be perfect. You can't ask any 'estimation' process to be exactly right.
Heck, even a recorded zero setting may not be perfect...two days in a row.
But, it should be close enough to limit the amount of ammo you waste hitting dirt.

CM