Question about “best” primers for 6.5CR load

[EchoDeltaSierra]

For my “match ammo” I have accumulated ample stock of Lapua brass, 140gr ELD pills, and H4350 powder. Since I just used up my last 800 CCI-450 primers loading up a bunch of 300BLK ammo, I though I’d solicit the group and see of there was a preferred small rifle primer. Should I just get a few more bricks of CCI-450s or is there a more favorable primer?

 

[dirthead1]

I did a test with my 6.5 Creedmoor, Lapua brass, RL26 powder and 147 eldm’s. I ran two ocw’s with identical powder charges, only changing from cci 450 to cci br4 primers. SD with the br4’s was half that of the 450’s. Mid teens with the 450’s and high single digits with the br4’s. I’ve read others say the two primers are exactly the same, but I’ve seen different results. I haven’t tried any other small rifle primers to compare.

 

[Onyx Z]

I did a test with my 6.5 Creedmoor, Lapua brass, RL26 powder and 147 eldm’s. I ran two ocw’s with identical powder charges, only changing from cci 450 to cci br4 primers. SD with the br4’s was half that of the 450’s. Mid teens with the 450’s and high single digits with the br4’s. I’ve read others say the two primers are exactly the same, but I’ve seen different results. I haven’t tried any other small rifle primers to compare.

CCI BR-4's are not magnum primers while the 450's are.

 

[dirthead1]

CCI BR-4's are not magnum primers while the 450's are.

Yes, I am aware of that.

 

[Supersubes]

CCI BR-4's are not magnum primers while the 450's are.

That actually isn’t true. According to cci, their cup thickness and brissance is identical to one another. The br-4 is simply designed to be more uniform primer to primer, and lot to lot.

Echo, how did the 450 work in your loads? If good, give some br-4’s a try. If you find no difference, go back to the 450’s and save yourself a bunch of money.

I’ve been working off the same lots of br-4’s and 450’s since the early early obummer years, because I bought a truck load of them. They’re absolutely identical for me.

 

[EchoDeltaSierra]

Echo, how did the 450 work in your loads? If good, give some br-4’s a try. If you find no difference, go back to the 450’s and save yourself a bunch of money.

Single digit SDs. I think I’m going to try the BR-4 primers to see any difference.

 

[LC 6.5 Shooter]

I have had better luck with the 450’s. I think I got a bad batch of BR-4’s and had like a 5-10% fail to fire rate. My current load Lapua Brass 4xf (annealed) H4350 42.0fg, FL resized with .289 bushing, 147eld produces a consistent single digit sd of 5-8. Avg 2715f/s.

 

[Conaso]

...note from CCI tech support.

Actually BR4s contain the same amount of priming mix as a CCI 400 so they are not a magnum primer. BR4s do have a thicker cup and are more consistent than the 400s which makes them our benchrest primer. CCI 450s have a magnum priming mix and a thicker cup like the BR4s but with a magnum priming mix rather than a standard.

 

[Supersubes]

...note from CCI tech support.

Actually BR4s contain the same amount of priming mix as a CCI 400 so they are not a magnum primer. BR4s do have a thicker cup and are more consistent than the 400s which makes them our benchrest primer. CCI 450s have a magnum priming mix and a thicker cup like the BR4s but with a magnum priming mix rather than a standard.

Guess I was wrong. If they’re adding more priming mix, I’d think there’s be a bump in velocity.

Here’s me test:

Alternating between them in 5 shot groups. 2 fps between them.

 

[Sniper260]

There is no best primer. You have to test them each time you do load development to see what your gun likes with given brass bullets and powder.

 

[ingraham]

From a safety standpoint, be aware that from brand to brand within a given type (ie large rifle standard, large rifle magnum) some primers are "hotter" than others. So, once you work up a load, if you switch brands, you may see different pressure for the the same powder lot/charge weight. Maybe someone here knows of a table that compares primer heat rates between manufacturers. I don't have one at my fingertips.