Is anyone using CCI SR in place of SP-magnum primers?

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IMtheNRA

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There was a post on ARFCOM a few weeks ago by a person who called CCI and was told that the two primers are identical and there is no technical reason not to substitute one for the other.

Now that I'm about to run out of SP-mag primers, I may need to use SR primers in my .357 mag loads.

Is anyone here substituting these primers, and if so, how's that working out for you?
 
I have loaded many hundreds to a few thousand 9mms with small rifle standard primers, mostly Federals, with no misfires and no "pressure signs." In fact, at one time Federal recommended their small rifle primer for .357 magnum because they did not then make a magnum pistol primer. I think you will be ok with CCI with the usual proviso of "working up" your load after a major component change.

I don't know about the source at CCI saying they were the same primer, though. I'd want to do some weighing and measuring.
 
I know of and have done that practice (SR for SPM) in 357 loads, however there is a
difference.

The cup is just a tad thicker with the rifle primers due to the increased pressures.

The Large rifle and Pistol primers are different in height as well. Punch a LP into a case
designed for LR and you will see the primer seat exceedingly deep.
 
I substituted CCI SR primers for std SP primers this year simply because they were all I could get. Essentially no difference in velocities of 2 loads that I tested over the chrono, a 38 spl load of 5.1 Unique/158 cast and 14.9 of WC820(similar to 296) and 170 gr SWC .357 load. The mag load had a slightly lower SD and the special load a slightly higher SD. Accuracy from my .357 rifle at 50 yds was the same with either primer. The only down side to SR primers is a slightly harder cup which only matters when firing some revolvers in DA.
 
Well, I tried this today and I'm not happy with the results. Here are some observations of the test batch of reloads.

.357 Magnum
Winchester 158-gr SJHP
Hodg. H-110 14.3 grains
CCI SR (bench rest) primer

These primers apparently are a bit stiffer than the magnum primers, as they did not seat slightly below flush, only flush with the casehead.

About 20% did not fire, even after repeat strikes. The revolver I was using has a very light trigger, but has had no trouble igniting thousands of CCI pistol primers. My stock 686 may be able to ignite the rest, but I did not bring it with me today.

The 12 yard groups were slightly larger than what I'm used to.

The brass came out significantly more dirty than usual, with lots of soot, but not much unburned powder. There appears to be a difference in primer flame quality between my usual SP-Mag and these SR-BR primers.

I guess my search for CCI SP-Mag primers will go on. :(
 
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