Evening Ken, this is just a thought that you may entertain on your computer: with all factors equal the velocity of projectiles of the same weight but of different diameters fired at equal pressures should differ by the ratio of the bore diameters to surface area. Rifling will cancel it self out with all factors equal. of course frontal area and atmospheric resistance comes into play but that too can be factored as a ratio, now see what you have done, my head hurts. <BR>I hope you didn't get the Idea that I was saying your explanation of ratios is incorrect. I was trying to say that using such a program to examine many different barrel materials through comparison would provide useful information the basis of which is the method you explained. This is just a tangent from the original idea.<P>Bullwnkl.<P>Jim
