bullet drop

[CPT.CRAZY]

I'm going to my first F class shoot soon I want to use my 6.5, help out with a starting point for drop shooting 123 amax at 2660 fps my drop from a 100 yrd zero to 600yrds should be how much in MOA?? Thanks in advance for the help.

[bwaites]

I'm going to my first F class shoot soon I want to use my 6.5, help out with a starting point for drop shooting 123 amax at 2660 fps my drop from a 100 yrd zero to 600yrds should be how much in MOA?? Thanks in advance for the help.

CPT, use this ballistic calculator, and print out the results:

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

The best answer to your question is to work through the information yourself. If you can't figure it out, come back and ask more questions, and we'll help!

[gonzaga]

I come up with 15.3 MOA at 600. But I punched that your sight in is at 1.5.
That should be pretty close.

Elevation would vary your results as well

[Nukes]

Assuming good zero, good chrono, good atmospheric, and using Litz's BC data for the 123gr Scenar, any ideas why the calculated ballistics tables would be way off (errors of 0.5 @ 200yds, 0.6 @ 500 yds from observed values)? The observed drops are considerably less than predicted by the tables.

Shooter, Kestrel Horus, and the online link above all agree in their calculations, but are 0.5-0.6 mil worse than observed.

With .308 and .338LM the tables have agreed within 0.0-0.2 of observed out to 800 yds.

[LR1955]

Assuming good zero, good chrono, good atmospheric, and using Litz's BC data for the 123gr Scenar, any ideas why the calculated ballistics tables would be way off (errors of 0.5 @ 200yds, 0.6 @ 500 yds from observed values)? The observed drops are considerably less than predicted by the tables.

Shooter, Kestrel Horus, and the online link above all agree in their calculations, but are 0.5-0.6 mil worse than observed.

With .308 and .338LM the tables have agreed within 0.0-0.2 of observed out to 800 yds.

Nukes:

If your ballistics program is accurate to under 1/2 mil @ 600, it is fine. You would have a real hard time trying to figure out what variables are involved and a harder time trying to figure out how much of that .6 M they account for.

You would also have to shoot a lot of ammo under identical environmental conditions to get a statistical sample that has any meaning.

At the longer ranges, seeing becomes an issue with dust, humidity, and other natural obscurants hindering a shooters ability to see well enough for perfect precision. If he is using hold overs, his accuracy lessens. Most of the time he has not measured the distance well enough and unless he is shooting on paper where he can measure shot groups accurately, he can be way off from something that is published. Most shooters have big problems calling their shots and without good, accurate, shot calls, it is almost impossible to figure out what is going on when faced with about any shooting issue.

Many guys shoot on steel and this must be the least accurate way of figuring out a zero. Unless you shoot through paper at a exact distance, and then measure a good statistical sample, you can't be sure what, if anything, is wrong.

Finally, there are a great number of ballistics programs out there that all give slightly different solutions. And, they tend to follow range bands with 500 or 600 being a dividing line with one program for the shorter distances and another for the longer ones.

I wouldn't get hung up over someones ballistics program not being perfect. Use them to get you close and then get your own data.

LR1955

[CPT.CRAZY]

Thanks for the help guys, I used the Strelok app on my phone and came up with 14.7 MOA that was close enough to get me on paper and zero from there.

[Nukes]

Nukes:

If your ballistics program is accurate to under 1/2 mil @ 600, it is fine. You would have a real hard time trying to figure out what variables are involved and a harder time trying to figure out how much of that .6 M they account for.

You would also have to shoot a lot of ammo under identical environmental conditions to get a statistical sample that has any meaning.

At the longer ranges, seeing becomes an issue with dust, humidity, and other natural obscurants hindering a shooters ability to see well enough for perfect precision. If he is using hold overs, his accuracy lessens. Most of the time he has not measured the distance well enough and unless he is shooting on paper where he can measure shot groups accurately, he can be way off from something that is published. Most shooters have big problems calling their shots and without good, accurate, shot calls, it is almost impossible to figure out what is going on when faced with about any shooting issue.

Many guys shoot on steel and this must be the least accurate way of figuring out a zero. Unless you shoot through paper at a exact distance, and then measure a good statistical sample, you can't be sure what, if anything, is wrong.

Finally, there are a great number of ballistics programs out there that all give slightly different solutions. And, they tend to follow range bands with 500 or 600 being a dividing line with one program for the shorter distances and another for the longer ones.

I wouldn't get hung up over someones ballistics program not being perfect. Use them to get you close and then get your own data.

LR1955

Thank you.

Maybe I have been spoiled to this point by having the programs agree with each other and also agree with observations within 0.0-0.2 mil.

Thanks again.

[LRRPF52]

CPT.CRAZY,

If you want your sighter to be closer on the day of the match, make sure you know your zero weather conditions, and then plug in the conditions for the morning of the match. Barometric pressure and temperature will be your biggest factors that will change the drop enough to be noticeable.

[Nukes]

A more accurate measurement of scope height cut the calculated/observed disparity in half.

[Jon A]

primary cause.