I've only used Remington and Lapua 260 brass and most of my Remington brass has loose primer pockets and I can't seem to get the Lapua brass to shoot as fast as the Remington. So, I was thinking of giving these a try.
https://www.eurooptic.com/Peterson-260-Remington-Casing-PCC260RM.aspx
https://www.eurooptic.com/Peterson-260-Remington-Casing-PCC260RM.aspx