A chronograph is one of the best investments you can make. I have a .243 Win M70 that follows the Hornady Manual exactly in velocity and charge weight. They used the same rifle to work up the loads. Its the only one I have that does that and the chrony confirmed it. Its easier to get where you want to be when you know where your starting from.

"Give a lazy man the toughest job, and he will find the easiest way to do it"