Re: .300 WSM brass questions
I will take a shot at question number one, it seems that bigbuck has given you some things to think about on question number two.
There are at least two reason for the loose primer pockets. First, Federal brass in some of the softest out there, and this can be the reason for the loose primer pockets. Second, hot loads stretch the brass and this leads to problems, so you are probably experiencing either one of the reasons or a combination of both.
I have used Federal, Winchester, Remington and Norma to load my 300WSM rifles. My opinion is that Norma is the very best. However,it is expensive and harder to come by. I have had good success with Remington brass, and Winchester brass although not as uniform and consistent as the Norma, or Remington will give you more than 2-3 reloads before stretching, unless your loads are too hot.