I are already on the lookout for new 22 Hornet brass for quite some time now. I found Prvi Partizan at Graf and Sons. I have use this producers item prior to now. I found this could be prevented, both by reducing velocity or using the Hornady twenty five grainers. https://rafaeldvlbr.blogpostie.com/48792958/5-simple-techniques-for-17-hornet-brass-in-stock