roadrash1970 (roadrash1970) wrote in guns,
roadrash1970
roadrash1970
guns

Range cards and calculators

I wanted to share an observation on one of the free online ballistic calculators I found prior to my latest class.


www.jbmballistics.com/ballistics/calculators/calculators.shtml click on the trajectory link and plug in your info. This calculator and the resulting sheet it displaced was shockingly accurate. The only date that I added (personally based on live fire was the windage adjustments).

Since I didn't have the weather info for the actual day, I reran the calculations with an accurate velocity as well as temp/humidity/altitude etc and reprinted. Note on the velocity: This latest batch which I reloaded was very consistent was had only a 10-15fps spread. What I found is that these are VERY VERY accurate sheets to put on the buttstock or wherever you want to store them.

I Compared the below numbers with the info I collected in my shooting log book for that day to confirm. In every case (100, 300, 500, 750 and 1000) these numbers were within .25 and .50 MOA of what I actually had on the turrets. So, those small deviations could easily be the result of my shooting, a slight wind or even a small variation in hold etc. Plan is to print out a few more of these for varied conditions and maybe a few extra blank columns on each so I could enter wind/correction data.

So, if you want to create one for your own rig and test it out, I'd highly recommend it. All things being equal and within reason, you should get a hit out at distance with maybe some tiny corrections if the wind or your hold is different, your mileage may vary :-)


.300WM Sierra MKBT 200gr 2850 fps Temp 80% Humidity 67%
Range Drop Drop V fps Mach Energy Windage 0-3 MPH
0 -2.3 2855 2.507 3620
50 -0.6 -1.1 2776 2.438 3422
100 0 0 2698 2.369 3232
150 -0.6 -0.4 2622 2.302 3051
200 -2.5 -1.2 2546 2.236 2879
250 -5.7 -2.2 2472 2.171 2714
300 -10.3 -3.3 2399 2.107 2556 .75 Left
350 -16.5 -4.5 2328 2.044 2406
400 -24.2 -5.8 2257 1.982 2262
450 -33.7 -7.1 2188 1.921 2125
500 -44.9 -8.6 2120 1.861 1995 1.25 Left
550 -58.1 -10.1 2053 1.802 1871
600 -73.4 -11.7 1986 1.744 1752
650 -90.9 -13.4 1922 1.687 1640
700 -110.7 -15.1 1858 1.632 1533
750 -133 -16.9 1796 1.577 1433 1.50 Left
800 -158.1 -18.9 1736 1.524 1338
850 -186 -20.9 1677 1.473 1249
900 -217 -23 1620 1.423 1165
950 -251.3 -25.3 1565 1.374 1087
1000 -289.2 -27.6 1512 1.327 1015 2.25 Left

For any of the reloaders out there, my recipe for this round is 69.2 grains of Reloader-22, Standard OAL of 3.340, a 200gr Sierra Match-king, Federal 210M Match primer. Cases were annealed and these were full length sized since I didn't have any once fired out of this chamber.

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