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What issue did you find with it? IME, there are programs a bit easier to use but none better than JBM. I wonder if you have an input/data error?I had been using JBM but it appears that their process has changed a bit. My range results vary from their calculations. I’d appreciate suggestions for other programs. Thanks.
I entered my velocity of 2942 FPS. When the calculation was done, the muzzle velocity appeared as 2762 FPS. I tried re-entering my MV and the calculation came back again as 2762 FPS. If I remember correctly, there used to be more information required such as twist rate and barrel length. I saw nowhere to plug those values into the program. The differences that I found were roughly .5 moa @ 300 yds. & a full moa @ 500 yds. I had much closer calculations the last time I used the JBM program .What issue did you find with it? IME, there are programs a bit easier to use but none better than JBM. I wonder if you have an input/data error?
I use JBM a lot. This weekend, I used it to calculate BC on several rifles/bullets and it was spot on.
The barrel twist, twist direction, bullet length, etc is in the JBM Trajectory—Drift calculator.I entered my velocity of 2942 FPS. When the calculation was done, the muzzle velocity appeared as 2762 FPS. I tried re-entering my MV and the calculation came back again as 2762 FPS. If I remember correctly, there used to be more information required such as twist rate and barrel length. I saw nowhere to plug those values into the program. The differences that I found were roughly .5 moa @ 300 yds. & a full moa @ 500 yds. I had much closer calculations the last time I used the JBM program .
Which of the calculators are you using? I do not believe JBM asks for barrel length. If you are using the "drift" calculator it does ask for twist rate, but I think that is the only one that does.I entered my velocity of 2942 FPS. When the calculation was done, the muzzle velocity appeared as 2762 FPS. I tried re-entering my MV and the calculation came back again as 2762 FPS. If I remember correctly, there used to be more information required such as twist rate and barrel length. I saw nowhere to plug those values into the program. The differences that I found were roughly .5 moa @ 300 yds. & a full moa @ 500 yds. I had much closer calculations the last time I used the JBM program .
That's strange. I also use Strelok as a backup to my Kestrel and it is within 1/10th. That is a LOT so I suspect one or more of the primary data entries is wrong, and by a considerable amount.I used Strelok Pro this weekend for going to 500 yards, correct speed, bullet, G7, scope, all. 1.3 MOA too much. Called for 8.3 and ended up being 7