Comparing Ballistics Calculations Using Litz’s BC and Lapua Radar Data
Lapua’s radar data available on their website opens up some interesting possibilities, for ballistics calculations we may not need to rely on BC’s and directly use the drag curves offered by Lapua.
I added the drag curve for 6.5 mm 139g Lapua Scenars into my ballistics solver, I chose this bullet as I shoot more 6.5mms than any other. My ballistics solver uses the same methodology as the one Bryan Litz includes with his book and it tends to match both Bryan’s and JBM’s solver. prior to writing my own solver I used JBM and found it to be very good so I use that as a benchmark to test my solver, I also use range data and Bryan’s solver.
The intent was to see what the compare the calculated results for three methods, my solver with Bryan’s G& BC and with Lapua’s radar data and then use JBM’s solver with Bryan’s G7 BC. Here are the results
Wade's Solver JBM
Range Speed Drop Litz Drop Radar Drop Litz
(yds) (ft/s) (inches) (inches) (in)
0 2750 -1.5 -1.5 -1.5
100 2591 0 0 0
200 2435 -3.69 -3.7 -3.7
300 2284 -13.26 -13.33 -13.3
400 2139 -29.51 -29.71 -29.6
500 2000 -53.38 -53.83 -53.5
600 1865 -85.97 -86.8 -86.1
700 1734 -128.6 -130.21 -128.9
800 1608 -182.83 -185.52 -183.3
900 1486 -250.56 -254.81 -251.2
1000 1369 -334.11 -340.56 -335
The third column is my solver with Bryan’s G7 BC, fourth column is my solver using Lapua’s provided drag curve and the final column is JBM’s solver using Bryan’s G7 BC. I included the JBM result to show that my solver which none of you have seen is close to JBM’s which many of you have experience with. The largest difference is at 1,000 yards (no surprise) and this is only 0.62, so it would take a better shooter than I to shoot and be able to tell the difference between the results calculated with Bryan’s BC or Lapua’s drag curve from radar data.
As Bryan Litz pointed out in an earlier post the radar data may give us an indication of what bullets cross the transonic gracefully.
I editted it to clean up the format of the table so it was easier to read.
Lapua’s radar data available on their website opens up some interesting possibilities, for ballistics calculations we may not need to rely on BC’s and directly use the drag curves offered by Lapua.
I added the drag curve for 6.5 mm 139g Lapua Scenars into my ballistics solver, I chose this bullet as I shoot more 6.5mms than any other. My ballistics solver uses the same methodology as the one Bryan Litz includes with his book and it tends to match both Bryan’s and JBM’s solver. prior to writing my own solver I used JBM and found it to be very good so I use that as a benchmark to test my solver, I also use range data and Bryan’s solver.
The intent was to see what the compare the calculated results for three methods, my solver with Bryan’s G& BC and with Lapua’s radar data and then use JBM’s solver with Bryan’s G7 BC. Here are the results
Wade's Solver JBM
Range Speed Drop Litz Drop Radar Drop Litz
(yds) (ft/s) (inches) (inches) (in)
0 2750 -1.5 -1.5 -1.5
100 2591 0 0 0
200 2435 -3.69 -3.7 -3.7
300 2284 -13.26 -13.33 -13.3
400 2139 -29.51 -29.71 -29.6
500 2000 -53.38 -53.83 -53.5
600 1865 -85.97 -86.8 -86.1
700 1734 -128.6 -130.21 -128.9
800 1608 -182.83 -185.52 -183.3
900 1486 -250.56 -254.81 -251.2
1000 1369 -334.11 -340.56 -335
The third column is my solver with Bryan’s G7 BC, fourth column is my solver using Lapua’s provided drag curve and the final column is JBM’s solver using Bryan’s G7 BC. I included the JBM result to show that my solver which none of you have seen is close to JBM’s which many of you have experience with. The largest difference is at 1,000 yards (no surprise) and this is only 0.62, so it would take a better shooter than I to shoot and be able to tell the difference between the results calculated with Bryan’s BC or Lapua’s drag curve from radar data.
As Bryan Litz pointed out in an earlier post the radar data may give us an indication of what bullets cross the transonic gracefully.
I editted it to clean up the format of the table so it was easier to read.
