ballistics chart?

[dragman]

When building chart I always zero at 100 with my chosen load. Then test it out long (1050) then to build my chart I adjust the speed to make the program work. I know the BC is what is changing but the speeds easier to adjust. How does every one else do it? I had too add 88fps to make my current rig match and its perfect from 100-1400.

 

[jmitchell135]

I think you are doing it right as long as you are taking an average bc and not the highest bc that the bullet is capable of. After the bullet goes subsonic though you have to adjust the bc to get it to work.

That's why some of the bullet companies post variable bcs. Bc changes with speed

I was taught take the average bc, put it in a calculator, find where the bullet goes subsonic, then set a target 100 yards before the yardage it goes subsonic at. Fire a group and Take the true adjustment it takes to get a zero at that distance and calculate it out. Your calculator will change your velocity.

 

[WildRose]

I do it basically the same way you are but in truth it doesn't matter if you are adjusting BC or velocity or both as long as you are validating your drops at range.

Once you have an accurate drop chart it really doesn't matter how you got there.

 

[FearNoWind]

...
Once you have an accurate drop chart it really doesn't matter how you got there.

Ditto ......... gun)
I do my zero at 200, run a preliminary ballistics chart with that data, then take five round samples at 200, 300, 500, 600, 800, 900 and 1K. My water line tells me how accurate the preliminary dope sheet truly is. I plug the water line averages into the equation, compare them with my dope sheet, use appropriate averages to do the math for the new settings and test again. That usually produces the final true values I need for a given load.

 

[WildRose]

Ditto ......... gun)
I do my zero at 200, run a preliminary ballistics chart with that data, then take five round samples at 200, 300, 500, 600, 800, 900 and 1K. My water line tells me how accurate the preliminary dope sheet truly is. I plug the water line averages into the equation, compare them with my dope sheet, use appropriate averages to do the math for the new settings and test again. That usually produces the final true values I need for a given load.

I never trust a calculator over a dope sheet.

There are errors built into every calculation, validated drop charts however are accurate as long as the load and elevation remain constant. Even if the barometric pressure is significantly different it won't change the POI enough to matter.

 

[dragman]

After I get the base from my verified shots I adjust for east/west angled and temp from my own experience.
Figure that was normal just like to see what everyone else does.

 

[Greyfox]

I think that actual range verification for drops trumps all else, particularly if conditions are pretty constant where you are shooting. Out past 700-800 yards it can get trickier if encountering material changes in temperature, elevation, angle, etc. I initially started my long range shooting quite similar to the OP's approach and did well. Given the BC's are well established, I would tune with velocity. Over time, particularly when I began to hunt in differing locations, I felt the desire to see if I could accurately align my drop charts with the ballistic devices using actual BC and velocity inputs. It took a couple of years, but I did eventually get there and now have high confidence using Shooter and/or my g7 rangefinder. I will still always test my zero, and a long range verification shot(s) when changing locations. I still keep a drop chart in my pack for back up though.

 

[stomp442]

Actual shot data is the only way to go. Calculators are great tools but they are only as good as the information input into them. Forget one setting, fat finger a number in the heat of the moment when you got a big buck in your sights or any number of things and you miss. I much prefer to look at a chart I made and verified dial and shoot.

 

[dragman]

Actual shot data is the only way to go. Calculators are great tools but they are only as good as the information input into them. Forget one setting, fat finger a number in the heat of the moment when you got a big buck in your sights or any number of things and you miss. I much prefer to look at a chart I made and verified dial and shoot.

I use paper charts so that is a non issue. Just pull up the chart for the temp and elevation then range and turn to the distance. Old school for me. gun)

 

[Canadian Bushman]

I use paper charts so that is a non issue. Just pull up the chart for the temp and elevation then range and turn to the distance. Old school for me. gun)

Some great shooters use this method, probably because it's fail safe

 

[Unofficial Gun Addict (UGA)]

I have found that for my purposes... I generally tweak my data in shooter to match my actual field results. I do this by BC and velocity tweaking, as well as using the velocity calibration tool. My dope in shooter is so close to what I see in the field... It's negligible... And not woth any additional refinement. Now if I was trying to shoot 4" groups at the exact poi at 1k... Perhaps I might change methodology. Perhaps not. Depends on what that particular dope was doing for me with shooter.