In my experience, primers make a difference as far as accuracy and point of impact go. I can't test for Standard Deviation or Extreme Spread yet, but I bet they make a difference in that department as well. An example, I have a 300 SAUM I reload for, I started with Remington 9 1/2 M primers, but wasn't getting the accuracy I wanted, so I switched to Federal GM215M and my groups shrunk to under an inch. Then, I ran out of those primers, and couldn't find any more for a couple years, so I switched again to CCI 250, which weren't quite as accurate, but only a little bit less, I used the same loads throughout all the primer switches. So, I'd say they do make a difference. As far as what brand to use starting out, it doesn't matter as long as you start low and work up, but they definitely have different effects on a given load. I've got a new chrongraph I've got to set up, then I can measure velocity, SD and ES, I bet I'll find some differences there as well.
If you're gonna be dumb, you better be tough
Last edited by SAUMHUNTER79; July 19, 2012 at 01:00 PM.