How much effect do different brands of primers really have on accuracy?

I ran out of 210Ms for my Palma Rifle. I very seldom shoot it on the bench. The last 10 shot group I fired at 100 yards with 210Ms measured .490.
Today I shot a 10 shot group with Winchester LR primers (everything else was the same). The group measured .392.

Did not shoot them over a Chrony.

Any other similar or different experiences.

BTW in NEED some LR primers if anybody knows where I can buy them.

quote:

How much effect do different brands of primers really have on accuracy?

No one has replied toyour question mostly (I think) because there is no answer.....it's something we all must test for ourselves....

Personally I'm of the opinion that primers have little effect on accuracy but many will post quite differently.....and their posts must be observed as evidence of differing opinions.

Depending upon all the different load paramaters, it could make a small change, or a HUGE change. You never know till you shoot it on paper.

quote:

Originally posted by N E 450 No2:
Depending upon all the different load paramaters, it could make a small change, or a HUGE change. You never know till you shoot it on paper.

This is very true. I have a 338-06, shoots sub MOA w/ my load & CCIBR primers. Change to Fed. or Fed. match or RP, groups open to 1 1/2". SO yes, it can male a big difference or it can make a little one like in your test.

The question of primers comes up over and over on AR.

People seem to be unaware that our host, Saeed, has done some tests on this question and has posted his results here. They are available at:

http://www.accuratereloading.com/primer.html

quote:

I ran out of 210Ms for my Palma Rifle. I very seldom shoot it on the bench. The last 10 shot group I fired at 100 yards with 210Ms measured .490.
Today I shot a 10 shot group with Winchester LR primers (everything else was the same). The group measured .392.

That's twenty shots all through a ring less than o.5 inch! (Unless the POI shifted - but that would be allowed with the change in primers). Saeed's results are presented slighly differently. Instead of adding the groups he has actually averaged them. Isn't that like dropping the worst shot by calling it a flyer? Am I missing something?