Anybody have LoadBase 2.0 Mobile (PDA version)?

[Eaglet]

Reading my post here on from 2-29-08, I want to say that I do use Exbal when I need info for a friend's gun using factory ammo since Exbal has a library for that, and also when I have on-site Barometric Pressure and don't want to convert to std barometric preassure. My baby load is calculated with Loadbase and manipulate the numbers so Exbal gives me the same results. It's jus fun having both of them running.

[mattj]

Eaglet, out of curiosity, do you use the chrono-at-different-ranges feature to calculate the drag coefficient value? I love the idea of having the customized drag function, but trying to shoot over a chrono at extended ranges scares the piss out of me. I once asked the author whether he could implement a feature that would calculate the drag curves based on drops at various ranges -- but he said that basically because of the way the calculations are done, drop measurements just aren't accurate enough to get good data for that... but man I would kill for a feature like Exbal has to tune based on field data without having to resort to chrono measurements and extended ranges.

I suppose you could try to tweak the drag curve by hand and try to find a value that matches observed drop values at known ranges, but I haven't attempted that exercise yet.

[Eaglet]

I know what you mean. I have not done it but is something that I think a lot about doing. I will eventually do it one of these days.
Try this: Use the velocities given by let's say Exbal, after putting in all the pertinent information. Use the velocities obtained there for 0, 100, 200, 300 yards and put them in LoadBase's DRAG COEFF of ANALYZER and calculate a new drop table using the drag coefficiente and Bc calculated by LoadBase. My experience has been awesome... my results are much closer to real life and have done very little tweaking to match bullet drop at long ranges after about 400 yards. You'll see that the first 500 yards on both tables are pretty close, but as you get further away the difference gets to be more significant.

From JBM Small Arms Ballistics:

(Q) Why can't I calculate BC from bullet drop at different ranges?
(A) You can, but not very accurately. If you look at the bullet drop for two bullets, one with a BC of 0.5 and the other with a BC of 0.55, you'll find that the bullet drops at 300 yards with a muzzle velocity of 3000 f/s and a 100 yard zero, are -10.9" and -10.7" respectively. So if you can shoot groups less than 0.2" at 300 yards, have at it. Of course you'll still only know the BC within about 10% (the BC calculation CGI can be as accurate as 2%!).

[mattj]

Thanks for the tip Eaglet, I'll definitely give that a try