What caused this?

[CastIronSkillet]

I always check a few sample pieces of new empty brass in my rifle to make sure it fits before I decide a path forward. I have never had an issue with Lapua but it is 2021 and anything is possible.

 

[Harvey_NW]

Update, I bought a new lot of brass this weekend and will need to size it all because apparently the chamber in my new rifle is on the tight side.

*inserts foot in mouth*