Which LR Primer for Stag10 6.5 Creedmoor with 140g bullet

[quikcolin]

Heading out today to grab some loading components. I have a brand new Stag10 with a 20" barrel, chambered in 6.5 Creedmoor. Going to grab a box of Hornady 140g bullets to start.... now trying to decide on which LR primer I should get? Any suggestions? CCI 250? CCI 450? The shop I'm going to is full of CCI and not much else.

Thanks!
Colin

 

[bobke]

You don’t need magnum primers to light off most all powders common to 6.5CM. And 450 is a small rifle magnum. I use BR2’s most often, Fed 210M as an alternate.

 

[quikcolin]

Don’t magnum primers have a harder shell, which makes them less prone to double fires in semi’s?

 

[bobke]

I shoot in several AR10 6.5CM’s and have never had any issues.

 

[XLR308]

Here is a reference sheet I've had for a long time for dimensional info on primers.
Save it in your reloading docs for future reference.
The other info allready given is solid with the exception of if you are shooting in sub zero conditions then the magnum primers may give more predictable performance.
The differences I think you were referencing for the milspec CCI 41 and 34 primers is they have a thicker cup and if I remember correctly the distance from the cup to the anvil is slightly wider.

 

[Anthonyc]

I would get the cci non-magnum ones. CCI cups are harder from what I’ve read in the past so I don’t think you need to worry about slam fires or other semi issues. I run the small (non magnum) CCI primers in a semi (224 Valkyrie) and never had an issue.

 

[XLR308]

I would get the cci non-magnum ones. CCI cups are harder from what I’ve read in the past so I don’t think you need to worry about slam fires or other semi issues. I run the small (non magnum) CCI primers in a semi (224 Valkyrie) and never had an issue.

If you are referring to the CCI 400 primers I would advise against running them in an AR.
The cups are not only thinner but they were not designed for cartridges running in the 55,000 psi and up range.
They will give false indications of pressure long before your brass will show any signs.
You also run the risk of blanking primers and torching the bolt face from gas leakage.
I have run quite a few of them in the past in a few AR's and actually had one slam fire, not from dropping the bolt on a round in the magazine but it double tapped after the shot.
I think you can get away with using them a bit more in a well designed bolt action with tight tolerances specifically the firing pin to bolt face fit and protrusion and running minimum headspace on you cases.
I use CCI 450 in several medium sized cases ( 6.5x47, 65 Creedmoor, and 308 win ) as well as all of my AR calibers ( 556, 68spc ) so I have standardized with what is most appropriate for the application instead of using something that is being pushed beyond its design limits.