Ever used the jbm trajectory calculator?

[JCP]

I was just curious if anyone has ever used and applied the data from the JBM trajectory calculator. If so how accurate was the info provided to actual point of impact at the distances you shot? I have read alot of reviews saying the tool is a really good one. Any info would be great.

[PoppaW]

I use JBM all the time to figure out trajectories and such. The info on that site is mind boggling. I think its best to double check your B.C. for your bullets if you use the drop down bullet finder as lots of companies have revised the B.C.'s for the worse lately and his drop downs may give a flatter trajectory. He may have updated these, I don't know. I have not taken the time to directly compare the print out to the targets yet so cannot comment that way but have heard it is good. If you can put in all your data accurately that is.

[Solothurn]

I can't comment on JBM, but use Exbal all the time, and can not believe we could ever really shoot without it.
To get the most benefit you need a Kestrel and a Chronograph.
With all the correct data entered into the Exbal program, I find I am ususally within about 1/2 moa variation from real world to what the program states, I suspect that JBM would be much the same.
I installed Exbal into my cellphone so have my ballistics computer with me everywhere I go.
For long range shooting and hunting these are a must have piece of kit in my opinion.

[coldredneck]

Have used JBM for a couple years now and find it very close to POI. Use a good chrony and pay attention to all the variables , temp , barometer , humidity , etc. Garbage in = Garbage out, but if you do your part it will put you very close to what to expect down range.

[Stinky Coyote]

i'm happy with it, just set up first rig with it, i used chrony and kestrel meter, zerod gun a 220, then shot to 360 and 498 yrds, counting the moa clicks need to get there....recorded the atmospheric conditions and brought that data home....

one thing i didn't have was the bc for the fusion ammo i was shooting, could not find it anywhere....so i guessed different bc's until the chart matched my actual field findings....i made a chart to 800 yrds with that data, and used it to shoot a rock across a valley at 701 yrds perfect.....so i'm pretty happy with that program....btw, use a bc of .465 for 130 grain .270 cal fusions for all you .270 shooters and you'll be real dang close to way out there

[JCP]

Thanks for the replies guys.

[LuckySeven]

I use the on line calculator all the time.....results are usually quite good !!!
I especially like the trajectory card for laminating or taping to the stock !!

http://www.eskimo.com/~jbm/calculati...traj_card.html