Bill, Jack...Thanks a lot! I forgot about sectional density. I did want that for sure. I've got everything working, but one thing was interesting. I had to drop from 4700 to 2500 in calculating the velocity to get the same results as on the Ballistics Corner. I checked several of my results with the Ballistics Corner for verification. This is what I have so far for calculations: sectional density, energy, recoil energy, recoil velocity, penetration and cavitation. The last two are based on an article posted by someone in one of our forums, but I can't find it right now. It's a thread that Marshall started, but I can't find it right now. I find all this interesting because now I can evaluate the relative effectivness of a load/gun combination and its associated recoil. I use a a baseline a gun/load that I have fired... in this case a 44M RH using Garrett Cartridges 330gr LBT cast @ 1385fps. If you have any other suggestions, I'd appreciate it. Also, this is a just Microsoft Excel spreadsheet, so if it's useful to you or anyone else, I think I can E-Mail it. I can try anyway. Again, both of you, thanks a lot.