Primers?

[Clo61]

I am newer to center fire reloading, but have reloaded 50k plus shot shells. The question I have is how big of a difference does just changing the primer make in a load? What would one expect to see in possible group size change or FPS? Any proven data would be welcomed. Example changing from CCI TO Federal. Yes I could go out and test it but I have 500 more primers to go.

Thanks

 

[Supersubes]

Very little change in terms of velocity or accuracy,

 

[TheOfficeT-Rex]

Measuring change is going to be highly specific to powder, charge, brass, and bullet. You may have slight velocity or ES/SD changes with a primer change, or even a slight accuracy edge. It's related to consistency and ignition of the priming compound and powder, some (rem 7 1/2) create quite the flame, while others (FGM205) are significantly milder. I wouldn't worry too much about it unless moving from a normal to a magnum primer.

And if that answer doesn't suit you, head to a benchrest forum and go down the rabbit hole. German Salazar did a pretty good writeup on primer differences, if you can find it.

I've noticed some differences between primers, but it's never enough to positively sway me from one brand to another, although i tend to stick to match primers (because ego, not because demonstrably better). I'm currently working through some FGMs, with a case of BR-2/4s in reserve.

 

[pmclaine]

I've come to the conclusion my only primer concern is the mechanical incompatibility of some types of primers with some brass.

Have been loading Winchester LRP for years in LC, WCC, KA and other brass with no issues.

Started loading FGMM brass with WLRP and I'm getting gas blow by scoring up my bolts.

Loading FGMM brass now with CCI 200s and there is no problem.

I will stick to other than Winchester primers for FC brass from now on.

 

[Yote Klr]

Historically I do load development with gm215m for large magnum cartridges, however two weeks ago I had a pierced primer on a 300rum 230otm and 93gr of n570... NOT an uneventful occurrence!!! Scared the crap out of me.

Swiched to cci250 and did a small load work-up to 93gr. No problems after switching, same velocity, better accuracy.

 

[Clo61]

Great replies...thanks for all the information. Done!