Barrel slows down after 300 rds?

What kind of Chrono are you using?

Magneto speed. It's N570 and the tested loads were 78.3-79 with and average of 3010. Last week 79 was 3044. And 79.5 was 3070. I don't have a drilled case so I am going to try some new ways to measure the lands and see where it has gone to. Thought about just moving the bullet 10 closer and see what happens. I did put a new battery in the chrono. I did have hits at 3010 at 835 yesterday.

Seems like I read somewhere , maybe Ryan Pierce not sure , But on avarage the 28 Loses a Thousands Throat erosion every 100 rds ...

I tried seating the bullets out 10 and 15 thousands further. It did pick up the speed but my accuracy and spread wasn't there. I am going back to my 2.998 measurement with 78.8 and checking accuracy. If it's still accurate then I will roll with 3010 and make sure it doesn't drop lower and kick me out of being accurate. The smith said he could cut the barrel back and re chamber 60 thou forward to get a little more out of it. Next barrel I am thinking about melonite or nitride.