I've read that changing primers can effect accuracy and ES when the right one is found. I've always wanted to test it for my self and am gearing up for it. How do you test your loads with different primers but keep the round count down to save barrel life and components? Since ES is a testing parameter, seems that 5 shot groups would be a minimum.
If you currently have a good load that you are real happy with 5 rounds will tell you more than enough. Don't change your powder, or the grains..just like you said...only the primer. I have used Fed 215 and Fed 210 for many many years and was blown away by the difference ( bad) that Fed 215 match made....stupid me... I thought WOW MATCH GRADE PRIMERS...bought a sleeve...1000 primers....jumped right in hook line and sinker. Loaded 50....shot ten rounds not believing the first five....thought maybe I had contracted super aggressive muscular dystrophy! Pulled 40 bullets, dumped the powder back, punched the primers out and through out 940 primers! So the short form morale of the story....5 should do it!How would you go about testing them without redoing a full load workup? 338 components aren't cheap and I'm on my last keg of Retumbo.
The best thing that ever happened was when my buddy borrowed mine and shot it, I then got a MS and Labradar and all the craziness went away. Same thing when I got a good scale, the FX120.... no more scratching my head.I have to say that I have chrony so standard errors and light conditions could be skewing my data.
This is true but to save you some time you could just use cci Primers , small rifle primers have proven to provide longer primer pocket life and better velocity spread so a cci 450 magnum with the 6.5 works well. I've gotten as low as 4 with mv so may work for you as well.I've read that changing primers can effect accuracy and ES when the right one is found. I've always wanted to test it for my self and am gearing up for it. How do you test your loads with different primers but keep the round count down to save barrel life and components? Since ES is a testing parameter, seems that 5 shot groups would be a minimum.
I've heard that LR primers in loads less than 70 grains can work better than magnum loads.