balistic program

[spartacus]

i have a question about balistic program: i tryed with berger, vortex lrbc and pejsa. so the first and second are quite the same out to 800 yards, but pejsa at 800 yards with 7rem 168vld berger has a different point impact of 9 inches...the difference to hit or miss a deer!
someone has the answer? which works better? others program to suggest me?
thanks a lot

 

[Nomad47]

I have a method that makes pejsa work fairly well.
First I run my ballistics on the JBM website out to 1200 yards. Then on the pejsa spreadsheet I adjust the "Retard coefficient Rate" and the "Standard Pressure" until scope correction and velocity at 1200 yards match.
An example: For my 284 Winchester shooting 180 Berger Hybrids, the Retard coefficient is .510 and the Standard Atmosphere is 1072. That is for an altitude of 950 feet and a muzzle velocity of 2850 fps. All other yardages are not exact but very, very close.

 

[lpreddick]

there are simple and complex programs. i am a varmint hunter(ghogs), so my target is small(at 400+ yards) and i don't get sighter shots very often. the hornady ballistic calculator is VERY simple and goes to 1000 yds in 100 yd increments. it requires just a few variables and if used you MUST enter your gun's "sight height"...distance from center of bore to center of scope. with a little math gymnastics, you can determine yardage point of impact for every click of your scope's elevation knob. i print a table and have it on the side of gun and after ranging the varmint, look at the table and click up to the clicks predetermined. have hit walking ghog at 532 yds and standing one at 522 yds. compared this program with some of the ones that are really complex and their data are about the same. i don't "holdover" anymore!

 

[Nomad47]

With a little math gymnastics, you can determine yardage point of impact for every click of your scope's elevation knob. i print a table and have it on the side of gun and after ranging the varmint, look at the table and click up to the clicks predetermined. have hit walking ghog at 532 yds and standing one at 522 yds. compared this program with some of the ones that are really complex and their data are about the same. i don't "holdover" anymore!

Your groundhog shooting is very similar to mine. I created a range card (in turret clicks) and keep it in my ammo box. The range card was created from the aforementioned pejsa spreadsheet. I sit at my portable bench, spot a chuck, range him, adjust the turrets, put the crosshairs right on him and squeeze the trigger. 368 chucks last summer in Ohio with 4 of them over 700 yards with my 243 wssm Match.

Where do you do your chuck hunting?

 

[wwbrown]

I have written a couple of ballistics programs that match JBM and a number of the commercial programs which is no surprise as we all start at the same equation. I have tested the programs with multiple bullets and calibers out to 1,200 yards. I use the output of the ballistics programs to get on paper, and they are almost always well within the black and only need a little tweaking to zero it. With sighters the output of the programs like JBM are almost always good enough to get a zero in a match.

I would not trust any of these programs to take a poke at a large animal without verifying my zeroes at ranges close to the range of the animal.

Just the way I do it,

wade

 

[spartacus]

thanks, nomad, but i'm a shooter for a short time, I need help: how do I interpret your chart? "Point of Impact 100" = zeroed at 100yards and 1 click reset to 171? with only a clik?, I do not think and then zeroed @197 yards with two clicks etc?
Then ,a question: 1 moa = 1 "@ 100yards, then, obviously 500yards 5 " ok! if the leupold turret is 1/4 ", and the bullet drop from 100yards to 500y is 20" I have to correct for 16 cliks?
in metric unit : 1/4 of inche = 0.635mm so @500yards 0.635x5= 3.175 , well, i have to correct for
20"=50.8cm , than 50.8/3.175= 16 click. is correct?
thanks a lot

 

[Nomad47]

Spartacus, the chart I posted was an example. It is for a specific rifle, bullet, velocity combination. The right side of the card shows the specific rifle, etc.
That rifle's zero for 197 yards is two clicks (1/2"). And you are correct - one inch of scope correction moves the POI (point of impact) two inches at 200 yards, four inches at 400 yards, etc. And you are correct on your metric conversion - you want to convert EVERYTHING to metric.