FWIW, there are a lot of "weird" headstamps out there that are not military. It's not like it used to be.
Chad already advised dropping back the powder, but I'd have a tendency to go back to the starting recommendations and work the load up again. Sometimes there are accuracy nodes that show up and weren't there before. I know that goes against common beliefs that a bullet going the same speed will have the same accuracy no matter what the brass, but changes in capacity and compression can also change burn rates a bit. Just saying .....
There's a fine line between BRAVE ... and STUPID.
The two most important days in your life are the day you are born and the day you find out why.