Henderson Precision power trimmer. I’ve had a Giraud and was having an issue with some cases not perfectly chamfered and deburred. The Henderson precision trims them perfectly and faster. I can do 100 cases in under 10 minutes all within .001.
I haven’t tried Starline but I can speak on Hornady brass. After the 3-4th firing the primer pockets were lose. I’d suggest spending a little more money and getting some small primer lapua brass. It will last you a long time if you anneal.
A lot of things could be going on. With the number of rounds you have through the barrel seeing velocity climb is normal in the 100-150 round range. The barrel is “ Settling In” and it will speed up. You could have developed a carbon ring in the chamber. Give it a good cleaning shoot about 15...