Range Report ballistic programs?

[42769vette]

so just out of curiosity i took my load and entered it into a program. im shooting a 260 with 140 amaxes @ 2760.

i have a real world drop chart. the program says i would be going 3125 fps to get the chart i made to line up.

the only thing i can think of is i have my scope height wrong in the program. i have it at 1.5 inches. my scope is a nf 5.5-22x56 and its mounted almost touching my #5 barrel.

i cant remember my whole chart and am not with the gun, but i know from a 200yd zero i have 8 3/4 moa drop @ 600 yds

any thoughts?

 

[Mod Adahy]

Re: ballistic programs?

Ballistic calculators are only as good as the info entered. Most online assume target and shooter are on same plane (ie no inclination or declination). Even worse is density altitude. Most just ask altitude and people enter the physical altitude when actually it wants DA. There are many draws to BC but once understood and applied correctly, they work fairly well. Remember, it is only as good as the data entered.

 

[42769vette]

Re: ballistic programs?

how would i go about finding my density altitude? im in indiana @ about 600ft above sea level

 

[MALLARD]

Re: ballistic programs?


http://wahiduddin.net/calc/calc_da.htm

does this help or no ?

 

[42769vette]

Re: ballistic programs?

probably helps some but i dont know what some of that stuff is.

 

[Notso]

Re: ballistic programs?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Azprc</div><div class="ubbcode-body">Ballistic calculators are only as good as the info entered. Most online assume target and shooter are on same plane (ie no inclination or declination).

Remember, it is only as good as the data entered. </div></div>

I've meticuolously measured my scope height, but I've always wondered if running a 20MOA base was skewing the numbers somehow. I also have very good chrono numbers, use absolute pressure from a Kestrel instead of corrected baro and am fairly anal about making sure the input data is as accurate as possible. My real world dope typically is .2 to .3 mils LESS than what the calculator says at all my ranges out to ~1000 yds. And I've used JBM, Ballistic and Bulletflight and they all show that my bullet needs to be doing 40-50 fps faster than what I show on my chrono.

Would a 20MOA base account for that?

 

[Swan]

Re: ballistic programs?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 42769vette</div><div class="ubbcode-body">so just out of curiosity i took my load and entered it into a program. im shooting a 260 with 140 amaxes @ 2760.

i have a real world drop chart. the program says i would be going 3125 fps to get the chart i made to line up.

the only thing i can think of is i have my scope height wrong in the program. i have it at 1.5 inches. my scope is a nf 5.5-22x56 and its mounted almost touching my #5 barrel.

i cant remember my whole chart and am not with the gun, but i know from a 200yd zero i have 8 3/4 moa drop @ 600 yds

any thoughts? </div></div>

Your scope height will have an effect on your dope, and 1.5" sounds a little low to me with a 56mm objective. The more likely cure for your problems is to use a Kestrel or other device to get your <span style="font-weight: bold"><span style="font-style: italic">station pressure</span></span> where you are shooting each and every time you go out and shoot. Closer than 600yds you may not notice a huge difference, but further out you most certainly will.

Kestrel is your friend, as long as you set it up correctly: http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Baro/

 

[Rarebreed93]

Re: ballistic programs?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 42769vette</div><div class="ubbcode-body">probably helps some but i dont know what some of that stuff is. </div></div>

If you will go to Wunderground.com, put in your zip code, you'll get today's info you need.
If you need that info for some other place your shooting, then put in the town or zip.