Re: New Barrel Velocity Increase at finish of Break in?
The issue here is pressure. If you're already running right up there pressure wise with your chosen load from the start, then you need to be aware that with most of the larger long range cartridges that your throat and the first bit of the barrel will roughen up a little somewhere between 25 to 50 rounds. This roughening will require you to drop your charge a grain or two to keep your pressures safe and velocities the same as when you started. The barrel then seems to settle and your load will stabilize for most of the rest of your barrel life. We always shoot the rifles we build for our customers long enough to get to this point. By the time we've broken the barrel in, done a close range load development, and long range validation, we're usually there. You don't want this pressure spike to happen halfway thru the first batch of ammo you've loaded and given to a customer!