I was priming my 284 case after firing and came across (1) that would not fit into my Lee "Auto prime" tool. Everything looked just fine on the outside.
Sooo! I Checked the extractor groove, It was .416! All the others were .404 - .406. Some as wide as .410! The 284s new are .404 - .406!
I had just cleaned, sized & deprimed them. So, I have no idea of which charge they recieved. Anywere between 39.5 to 42 of Lil gun with a 230grn. FMJ. My thoughts are, With a tight chamber and a good strong lock up! Where is the brass to go? The only place not supported. the extractor grove............. Any thoughts!!!!..........Anyone!!!!