Way too much math....why not just do like everybody else and claim at least 200 fps over the hottest factory load and never admit that you don't have a chrono??? I mean, if you really want to know the truth then you have to buy a chrono. If it's really not that big a deal to you then you might just as well have some fun. Kind of like endorsing a certain bore cleaner...people will listen to you as long as you forget to mention that you don't have a borescope either!!!!