Go with Pejsa software. The Horus ballistic program is the worst written ballistic program I've ever come across and I own 7 different ones. They use something called a C1 drag model. This drag model doesn't exist in any of my books on ballistics. I've called twice and send three emails asking to speak to someone who knows anything about the program. They refuse to return my calls or emails.
I played with their demo version and this is what I've discovered. The C1 drag model is nothing more than the G1 drag model that was created over 100 years ago. The Horrible "oops" Horus software matched the G1 drag model calculations I ran using there demo data information.
So what does this mean? The G1 drag model is based on a 1 inch 1 pound round rose projectile. This means they expect all bullet types such as a flat nose 45 ACP type bullet, and a flat base spire point, boat tail and a VLD bullet to have the same flight characteristics as a 1" 1lb round nose projectile.
Bottom line the program isn't just bad, it's just plain awful. Pejsa really understands ballistic and though I don't have that one, I've heard his program is very accurate.
Hope it helps.
[ 12-18-2003: Message edited by: Jeff In TX ]