Calculating Trajectory with Multiple Verticals

[Full Curl]

I'll try to explain this as best I can… If I have my vertical +/- POI numbers in inches at 100, 200, 300, 400, 500, and 600 yards, is there any software where I can input multiple "zero" verticals at multiple distances and then calculate the trajectory based off that?

I'm currently using Strelok Pro softrware. I can input a SINGLE "zero" range distance and corresponding vertical in inches.

I figure if I can input actual multiple POI numbers at multiple distances, I can "true" the trajectory even better. Thanks!

 

[orkan]

Doing that would be of little value, as the trajectory at distance is determined largely by environmental conditions.

Record the conditions during your live fire testing. Then you can use that data to compare against your ballistic computer to ensure accuracy of your firing solutions.

 

[Mikecr]

If at the correct local BC your G1, or G7 drag curves aren't validating in the field, you could go with PEJSA software & curve. If I remember right, Pejsa described in his book how to adjust constants in his math/software for needed shaping of bullet path. A Retardation constant.

 

[Barrelnut]

You can do it with Shooter. It's called Velocity Calibration. You can enter your validated drops for up to 5 targets at the distances you wish. It will then give you an adjusted muzzle velocity that you can use for the load entry. If that's what you're asking about.

 

[ShtrRdy]

Does your version of Strelok have the reticle you're using? I think there is a way to have it list the yardage for each vertical hash mark.

 

[C.O. Shooter]

[ame]http://m.youtube.com/watch?v=dWpTVbXlspk[/ame]

Maybe this will provide some insight!

 

[maninthemaze]

Just Google "Vortex Trajectory Validation". I think Vortex has a ballistic calculator the allows you to enter your drops and bullets BC and it will tell you the muzzle velocity.

 

[Full Curl]

orkan - yes, I understand the theory behind trajectory, but if I had all my environmental conditions for the day I shoot and then input different POI's at different distances with a given G1 BC, it could then calculate actual trajectory (beyond my last POI) and fps based off my inputs. I hope this makes some sense.

Mikecr - Not familiar with PEJSA software but will check it out.

Barrelbut - EXACTLY what I was looking for. I'll be checking Shooter out. THANKS!!

ShtrRdy - Yes, I use the reticle function in Strelok Pro. I'm shooting the Leupold B&C reticle with holdover hatches and Strelok's reticle function works great. I just can't get my G1 drag curve to match as close as I want to what the software is calculating it even using the "truing" functions. It's close but since I know my vertical POI's at 100, 200, 300, 400, 500, and 600 I should be able to input all of those and then have the software build the curve and fps based off those.

Thanks for all the feedback!

 

[Full Curl]

C.O. Shooter - I haven't watched the video yet, but will. Thank you.

 

[orkan]

orkan - yes, I understand the theory behind trajectory, but if I had all my environmental conditions for the day I shoot and then input different POI's at different distances with a given G1 BC, it could then calculate actual trajectory (beyond my last POI) and fps based off my inputs. I hope this makes some sense.

Your DOPE serves as a guide, nothing more. The only time it would be accurate would be when conditions were identical. This is why we compute firing solutions. Actual DOPE has value, and educated guesses can be made on firing solutions in various conditions using that DOPE, but that is all they are, guesses.

Temperature is our method for determining air density, which is decidedly different than air pressure. A trajectory recorded during actual firing in a 90 degree condition will not match that of a 30 degree condition. This change in trajectory is not linear, but a curve.

The tools to make these computations are available. Both with electronics and with physical devices. There is no reason not to take advantage of them. Then shoot at distance and verify the chosen device's ability to predict a firing solution correctly.

 

[Full Curl]

C.O. Shooter - video really helped, thank you.

When I use the "Validate" function in the Vortex LRBC I'm confused on the "Elevation Dialed". I don't touch my turrets and just hold dead on at longer range and then measure my drop. Therefore, I put "0" in for Elevation Dialed and then my bullet drop in inches and it comes out with a crazy 4000+fps number...??? I also have no idea what units of measure the "Total Experienced Drop" figure is in. Am I using the program correctly or am I missing something since I'm not touching my turrets? I'm only using the "Validation Group #1".

Also wondering how much effect barrel heat can have on POI at shorter and longer distances? I typically let mine cool enough so it's not hot, only warm to the touch but it's much warmer than when it's cool. Just wondering if the effect is minimal or not and a possible cause for a slight shift in POI from what the data suggests...???

 

[Full Curl]

orkan - thank you for the explanation. I'm starting to have a better understanding of the whole trajectory thing. I was playing with some temp numbers and see that it really does not play much of a role out to maybe 300 yards but then starts being multiple inches in POI difference after that... like you said, just have to shoot and verify. Now I just need some 20 and 30 degree temps in August