New JBM range card

[fr3db3ar]

So far I don't find that it works very well using Mil-dot. Either I lose 200 yards between 100 and 300 or it only goes up to 3 with 2 being above and below that.

IE

Trajectory μCard - Constant Drop Handi Rifle .223 55 gr 3240 fps # Range Drop Wind # Range Drop Wind
(yd) (mil) (mil)
(yd) (mil) (mil) 1 101 4.00 0.28... 6 666 -1.00 2.72
......................2 306 3.00 0.97 ... 7 724 -2.00 3.07
.......................3 427 2.00 1.46... 8 775 -3.00 3.40
.......................4 522 1.00 1.92... 9 822 -4.00 3.70
.......................5 600 -0.00 2.33... 10 864 -5.00 3.97
10/08/09 11:33, JBM/jbmucardd-5.0.cgi

and
Trajectory μCard - Constant Drop Handi Rifle .223 55 gr 3240 fps # Range Drop Wind # Range Drop Wind
(yd) (mil) (mil)
(yd) (mil) (mil) 1 50 1.00 0.14..... 6 582 -2.00 2.23
.......................2 101 2.00 0.28... 7 651 -3.00 2.63
.......................3 270 1.00 0.83... 8 711 -4.00 2.99
.......................4 400 -0.00 1.35... 9 763 -5.00 3.32
.......................5 500 -1.00 1.81



10/08/09 11:09, JBM/jbmucardd-5.0.cgi

 

[AJ Peacock]

So far I don't find that it works very well using Mil-dot. Either I lose 200 yards between 100 and 300 or it only goes up to 3 with 2 being above and below that.

IE

1 101 4
2 311 3
3 431 2
4 525 1
5 603 0
6 669 -1
7 727 -2
8 778 -3
9 824 -4
10 866 -5

and
Trajectory μCard - Constant Drop Handi Rifle .223 55 gr 3240 fps # Range Drop Wind # Range Drop Wind
(yd) (mil) (mil)
(yd) (mil) (mil) 1 50 1.00 0.14 6 582 -2.00 2.23 2 101 2.00 0.28 7 651 -3.00 2.63 3 270 1.00 0.83 8 711 -4.00 2.99 4 400 -0.00 1.35 9 763 -5.00 3.32 5 500 -1.00 1.81



10/08/09 11:09, JBM/jbmucardd-5.0.cgi

I don't understand, are you saying it's incorrect or that you don't like that there isn't a line for each of 100, 200 and 300 yd areas? Since a mil is 3.6moa, it makes sense that at the closer ranges, a mil change in point of aim will cause more than 100yds of point of impact change.

AJ

 

[fr3db3ar]

You are correct that the closer is more change. I'm going to quit trying to fuss with it and just tell it I have -9 steps and start zero @ 100 and see what it gives me. Unfortunately it's unlike that I'll ever be using a NightForce scope, as nice as they are.

Well I ran it up with .25 mil dot intervals and I believe that will be quite acceptable. The card is a bit bigger....but it'll do.

 

[LouBoyd]

Obviously a mil-dot reticle is not high resolution. However, you can run the program with 1/4 or even 1/10 mi steps and interpolate between the dots. You should NOT estimate by a portion of the range distance as that is not linear, but a chart which predicts 10ths of mils will be accurate if you simply estimate the linear distnce between the dots.