CCI 400 vs CCI 550

[Nick_C_S]

Is the CCI 400 small rifle primer really the same as a CCI 550 magnum small pistol primer?

I know there's been tons of chatter about it over the years here on TFL, but what is the true "yes" or "no." to the question?

And yes, I'm asking because I'm running low on 400's. I have tons of 550's. I did pretty good stocking up when the previous administration was in office, but rifle primers were my weak spot. I was looking for #34's and never found any - I shoulda just got more 400's. Besides, I have yet to get a slam-fire; and I'm beginning to think that concern is mostly a myth. I digress. What about 400's vs 550's?

 

[Unclenick]

If you search YouTube, you'll find two conflicting test results on this. One is in 9 mm, for which there appeared to be no perceptible difference. The other was in a carbine load (forget which chambering), and it found a performance difference. Twenty years ago, the lady answering the phone at CCI told me CCI's employees all bought the 400s for both rifle and magnum handguns as the cup and priming mix and its quantity were all the same, and the 400s were priced lower because the box didn't say "magnum" anywhere on it. Only the package and price differed. But primer specs change over time, so you can't count on that to be true twenty years later.

I tried to get some current production 550s and 400s at the outset of COVID to chronograph from a 38 Special revolver with molded wax bullets. I got the flash holes drilled out on six new Starline cases. and everything ready. Unfortunately, I was about two days late and missed my chance to get the primers from a LGS. Someday, when they are available at less insane prices again, I will finish the experiment.

 

[Nick_C_S]

Thanks Unclenick. That's good enough for me.

I might just load up a few 223 rounds (for AR-15) w/ 550's, just to test.

All I care about is if it lights, sends the bullet downrange, cycles the action, and does no damage to the firearm. Bottom line performance is secondary at this point.