Conversation With CCI Tech About SPM vs SR Primers

[COSteve]

I posted this on another site last summer and forgot about it. I happened to find my MSWord document of it so I thought I'd share. This is from a conversation on June 14, 2009 with CCI's tech dept.

I called not to complain about availability, but rather to discuss the technical differences between their primer types. I was put in touch with one of their tech reps who was very happy to discuss their primers. BTW, She mentioned that she had worked there 38 yrs and never seen anything even close to this kind of demand.

Then she said that they can produce 3 million primer per day flat out (which they are currently running) but have currently over 1 Billion back ordered. Unfortunately, that means that if all new orders stopped completely today. Everything; ammo, gov't, and component, it would take almost a year running flat out to catch up.

Anyway, I was asking about the cup thickness, formula differences, and formula amount differences between their #500 (SP), #550 (SPM), and #400 (SR). She had me hold a minute to get the detail specs up on her screen and this is what she said.

Cup thickness: The #500 has a thinner cup than either the #550 or #400, however, both the #550 and #400 have the same cup dimensions (including thickness).

Flash powder formula: All three sizes use the same formula for the flash powder.

Flash powder amount: The #500 has a slightly smaller amount (3 micrograms) than the #550 or #400 which both have the same amount.

I asked if the SR primers could be used as an acceptable substitute for the SPM primers. She compared the #550 and #400 and then replied that yes, they appeared to have the same specs, same dimensions, same cup thickness, same formula, and same amount of flash powder. She even noted that the SPM primers were slightly taller than the SP primers and were spec'd the same dimensions as the #400.

I asked if she knew any reason not to just use SR primers for both magnum pistol and rifle applications based upon that information and she said that many there only bought rifle primers and used them for all their reloading, magnum or not. The only exception being for custom pistols where the thicker rifle cup contributed to misfires, which she said only occurred in custom race pistols.

[Terry Murbach]

INTERESTING !!!

[okdee]

pretty Interesting! Thanks for the replay!

This naturally makes me wonder about the other companies that make primers. Winchester and Federal come to mind.

I seem to recall a story in the NRA magazine that covered the primer manufactor and testing processes by the big 3. Kinda of fuzzy, but I seem to half remember, that the ingrediants were all the same, but certain parts of the process were different for each company. The end of the story seem to imply that there just was not much difference in the final product, when compared company by company. Try telling that to reloaders!

I may try to revisit that mag, I know its somewhere in that room!

[w30wcf]

COSteve,

Thank you for the most interesting post! I have often wondered if they were the same or similar. Thank you for clearing that up.

I don't think the same can be said for the WSR & WSPM primers. I have tested them side by side in selected loads and the WSR's produce a bit more velocity. They are pretty close though.

w30wcf

[COSteve]

I know its somewhere in that room!

Those very words have gotten me into some long searches with nothing to show for it at the end!!!

[Griff]

Hmmm... maybe a sorta placebo effect. You think there's difference, therefore there is!

I believe the thicker cup on rifle primers is common to all manufacturers.

[J Miller]

I've never had any use for small rifle primers. Now if I see a good deal on some I'll grab them. I got a couple of 357s to use them in.

Joe

[Rimfire McNutjob]

She blessed us with some pretty good info I'd say. Sounds like you hit the jackpot there.

[retmech]

At the time I did not have any CCI sp primers to compare but this thread shows a comparison of CCI small rifle versus Mag tech small pistol.
http://castboolits.gunloads.com/showthr ... ht=fecmech

[AJMD429]

I seem to recall a story in the NRA magazine that covered the primer manufactor and testing processes by the big 3. I may try to revisit that mag, I know its somewhere in that room!

If you find it, please try to post scans or a link or something. Sounds interesting!

[El Chivo]

thanks for the info - that is good news. I use the #550's and they have been out, and our store always seems to have small rifle primers.

Although I'm good for now, since I've been hoarding primers, the day may come when I'll need to use the small rifles.