Small rifle magnum primers

[Doug30racer]

I have a piercing issue with my 20 practical and I am interested in trying the cci 450 instead of the 400. I was wondering if or how much hotter they are than the cci 400?

 

[Oso]

If you have a piercing issue then why not just try the CCI #41, which are Military Small Rifle Magnum with hardened primer cup designed to reduce chance of slam firing in AR15/M16

 

[Tim s]

Probably the same cup, go with Rem 7 1/2’s

 

[IHFarmer07]

From my limited experience and research with primers is that cci400 and cci450 are close to the same other than the thicker cup. I also tested the cci41 and found its like the cci450 with the harder cup but I got a bit more velocity.

https://www.6mmbr.com/PrimerPix.html

https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/

 

[Doug30racer]

From my limited experience and research with primers is that cci400 and cci450 are close to the same other than the thicker cup. I also tested the cci41 and found its like the cci450 with the harder cup but I got a bit more velocity.

https://www.6mmbr.com/PrimerPix.html

https://www.accurateshooter.com/technical-articles/primers-and-pressure-analysis/

Thanks for the info, was looking for facts and numbers.

 

[IHFarmer07]

Thanks for the info, was looking for facts and numbers.

No problem

 

[mikeinct]

I switched from Standard SRP to CCI 450's I have not pierced one yet... Mike in Ct

 

[acloco]

Chart from Calhoun.

http://www.jamescalhoon.com/primers_and_pressure.php

 

[Oso]

I always forget to reference Calhoun's report...good stuff!

 

[17VLD]

When dealing with small rifle primers, a lot of the piercing issues can be traced back to the diameter of the firing pin hole being to large.Greg Tannel will bush the bolt face for a reasonable price and for this job his turn around is fast.I did a lot of testing with the 450 v 400 in my 20 Dasher and can say that I did get better more consistent accuracy with the 450.
People have said when switching to a faster hotter primer drop 1.0 grain of your powder and work back up.Be safe and definitely try the 450 first.
Greg’s bushed bolt with be worth the time and money,but be aware once done it is harder to notice an over pressure load just from looking at the primer.
Matt

 

[chuckshooter]

I run 450's in most of my varmint rig's because of the thicker cup, .020 for the 400's and .025 for the 450's . my general number is about a 1/2 grain in difference between the two is this caliber group. 450's are a magnum primmer so less powder is needed with them. I currently load for 5 of these and all are running the 450's. as 17vld said, you can have an issue with the firing pin,needs bushing? or a rough tip?
if you would post your load and type of rifle, it would give us a little more info to go on.

 

[Lefty Trigger]

Probably the same cup, go with Rem 7 1/2’s

The Remington 7 1/2 is the hottest small rifle primer out there. I have done a lot of testing with primers and the 7 1/2 will add around 40 to 60FPS to a standard load which could push hot loads over the edge. Other primers don't show this kind of increase. But you are right about the cups being harder, just saying you might need to back down a load switching to the 7 1/2's

 

[Tim s]

The Remington 7 1/2 is the hottest small rifle primer out there. I have done a lot of testing with primers and the 7 1/2 will add around 40 to 60FPS to a standard load which could push hot loads over the edge. Other primers don't show this kind of increase. But you are right about the cups being harder, just saying you might need to back down a load switching to the 7 1/2's

Yep, and, in point of fact, you can probably make a case that if the OP is piercing primers, maybe he should back down for a couple reasons.