Small rifle primers CCI 450s vs CCI 400s for a 6BR

Colt1776

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So why do so many people use CCI 450s when it comes to the 6BR? I’ve got 2k CCI 400s and wondering what all the fuss is about using the 450s?
 

Codiekfx400

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If you have Remington 7.5 primers those have the thicker cup and will work as well.
 

MilSpecOkie

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450 has a thicker cup for higher pressures
I use 450s in a large firing pin/unbushed bolt for the reasons mentioned above. My question is if you use a small pin/bushed bolt combo do you still need the thicker cups or will the 400 have enough support then?
 

Milo 2.5

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450 has a thicker cup for higher pressures
I was always under the assumption that thicker cup small rifle primers were made to reduce slam fires in AR's. People choose to use them for others reasons such as higher pressures.
 
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MilSpecOkie

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That is to prevent slam fires. So yes, they also use thicker cups in military rounds.
 

Colt1776

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So other than being a few thousands thicker do the 450s put out more energy than the 400s?

Because I have 2k of them and just got a 6br barrel spun up I am running it on an Impact so it has the small firing pin.

Would I get better performance out of the 450s?