Do primers matter???

[TheRidgeRunner]

Hi all,
Just wondering if anyone has any first hand experience with several types and brands of primers. I have been reloading for close to 5 years now, but never considered if primer brand has any effect on accuracy. Any info is greatly appreciated. thank you and God bless.

 

[dok7mm]

Yes, primers can make a real difference on grouping and/or changes in velocity, in some cases. I do my work up with Federal match primers, but always test CCIs to see if there is any improvement.

 

[MudRunner2005]

Hi all,
Just wondering if anyone has any first hand experience with several types and brands of primers. I have been reloading for close to 5 years now, but never considered if primer brand has any effect on accuracy. Any info is greatly appreciated. thank you and God bless.

Simple answer, YES, they can.

I never interchange brands for a particular load. When I test a load, I stick with that brand and model primer. I might test another equal primer (Fed 215M vs. CCI 250) to see if it improves the load, and sometimes it does, sometimes it makes it worse. But typically if I try a different primer, I'm working up a whole new load.

 

[TheRidgeRunner]

Simple answer, YES, they can.

I never interchange brands for a particular load. When I test a load, I stick with that brand and model primer. I might test another equal primer (Fed 215M vs. CCI 250) to see if it improves the load, and sometimes it does, sometimes it makes it worse. But typically if I try a different primer, I'm working up a whole new load.

Thanks for the insight I'll be sure to try out equal primers.

 

[MudRunner2005]

I recommend starting a new load workup if you try different primers. Just swapping one for anther is not a safe idea, and I highly DON'T recommend doing that. Different primes, even ones of equal rating, are not always going to ignite the same. And if one is hotter than the old one you were using, it can cause pressure spikes and cause a catastrophic failure, and hurt your gun, or even you or someone else around you.

So, like I said, swapping primers around, I recommend doing a whole new load workup, or at least start about 1/2 to 1 grain lower powder charge than your old load, and work up from there.

 

[Greyfox]

Yes, using different primers can make a difference. It might be overkill, but for my "high precision" LR hunting and competition loads, I will try to use the "same lot" of primer, as I will with powder, bullet case, to insure consistency.

 

[Mike 338]

If the gun shoots well, there's probably no reason to change primers. I have an '06 that mostly shoots 1 moa or just a smidge worse. Different bullets/powders didn't help. Tried primers as a last ditch test. One cut the groups in half, consistently. It shoots very well now. Other rifles that I tested have shown negligible results. The answer to the question is that changing primers may make little or no difference or may make a huge difference. You just gotta test 'em.

 

[Pdvdh]

Only one way to determine if they make a difference with your rifle, and load? Time and materials.

Every change to your load can make a difference. It all takes time and materials. Eventually you tire of the time and materials expended, and accept what you've got. OR... $Re-barrel$

And then start all over again

 

[MagnumManiac]

Yes, I test with 3 types of primers when developing a load.
I start with the bullet, then powder and load 3 identical sets with the only difference being the primer.
I have often found Winchester primers tighten groups up over Federal primers in the same TYPE. So a magnum primer in the Win generally shoots tighter than the same Fed primer, but not always.
I have had Fed 215's print the tightest groups even in standard cartridges like the 6.5-284, 6.5x55 and 25-06.
Also had best groups in 338WM with standard WLR primers. However, this was only one instance with one powder/bullet combo, not at all what happened with every bullet/powder combo.

I have also seen a load with a certain powder and bullet spray them all over the target, a simple primer change made all the difference on a bullet/powder that looked like it had no chance of performing at all in that barrel.

Cheers.

 

[Lefty7mmstw]

another thing that changes with primers is the amount of fouling they leave. I always gravitate to fed and win primers as they are cleaner burning, while I try to stay away from CCI as they will leave a lot more fouling (remmy is in the middle). I need to re-test again as my primer testing for flame intensity and fouling was done years ago, but most of the primers I own were bought years ago too...

 

[Bradu]

I had issues with Winchester printers several years ago that were pinholing on the edge of the cup and flattened real bad with the minimum load. Switched to CCI and lost 50 fps but sd's went from double digits to single digits.

 

[Greyfox]

My go-to's are Fed210M and 215M for LR and Magnum. primers. CCI BR4 and 450's for small primers SR and Magnum(large case). If fine tuning is needed(not too often), I'll swap between Fed and CCI, or try Winchesters.

 

[Mikecr]

As you can see -it's an abstract.
I have a theory that it's not the primer directly, but the primer AND your striking of it.

I once had a firing pin slipping within it's cocking piece. The ammo fired as normal, but suddenly ~2 out of 5 shots were throwing out of groups. This was intermittent(the pin moved back & forth here & there), not easy to find, but when I did, I had to determine where the pin was set when i had worked up the load. That's when I discovered that there is no standard here.
So I did firing pin setting testing, just like bullet seating testing, with my standard primer for the load (205 Feds).
My pin adjustments where measured as released pin protrusion from boltface. In this case the pin is secured with set screws.

What I observed was grouping opening and closing in apparent nodes.
I chose the tightest setting of course, and it ended up this problem turned into a blessing. I found grouping better than load development itself had produced.
The gun went from solid 3/8moa, to ~1/2moa (with the problem), to solid 1/4moa with the pin set at optimum for the primer. That's huge. I never would have arrived there without that testing.
Out of curiosity, I tried the same testing with CCIs, and the optimum setting was significantly different. But I had already comitted to Feds with this gun, so I went back to them with their best pin setting.

It would do no good to declare MY settings, as they would not likely be yours. My firing pins are different diameters, mass, driven by different springs, with different sear release, etc. It's a local abstract.

 

[Buska]

I'm no pro but like to tinker simple answer, yes. Depending on the load and rifle you could tighten a group, lower ES, improve velocity, or opposite of all those things. Just like tweaking coal, or charge a little, right? It's fun to play with, try a few and see what happens!