SR Magnum Primers for 357

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PapaWheelie

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Due to availability I have been using small pistol, small pistol magnum and small rifle primers interchangeably in my .357 686 for my down loaded target/plinking loads. I have never seen any real difference either in accuracy or pressure signs.

The go to load for me is 5.2 grains True Blue with a 158g SWC in full length 357 brass which should produce in the 950 fps range.

By mistake I bought a small quantity small rifle magnum primers, CCI 450. From what I've been able to read, the only difference between SR and SRM is the thickness of the cup. Does anyone have thoughts on using the small rifle magnums for plinking loads.

To be clear, when loading full power 357's I use ONLY small pistol magnum primers.
 
As long as your revolver will reliably ignite them, I personally don't see a problem. Many competitive action pistol shooters have been using SRPs of various types in handguns for decades.
 
Now a days, with the primer shortage.......
what ever "floats your boat" is how it is getting done, in these times.

If it fits in the hole..............
and goes "Bang", you are doing well, in the game of reloading.

Brand "Y" is a good thing, today if it can be found on a shelf !!
 
Thanks all, I appreciate the input.
 
Go for it. I have been loading LP Magnums in all My large pistol brass for decades. Including 45 ACP.
 
dave1918a2 said:
Go for it. I have been loading LP Magnums in all My large pistol brass for decades. Including 45 ACP.
Click to expand...

Actually, if you're using Winchester LPP they only have one flavor rated for both standard or magnum use. If it was unsafe they would never do that.
 
I researched this a bunch. Most info says the only difference between SR and SP primers is SR are slightly harder to ignite.
My experiments are limited, but I loaded 50 ea .380 and 9mm using some very old Remington SR primers. I no difference noticed at all. They all went bang. The .380s went through my Ruger LCP. The 9mm's through my wife's M&P.
 
I've been using BR4s behind H110 for about a year and the light the prettiest fireball I've ever seen, with no signs of over pressure...
 
Other than maybe a harder primer cup, SR and SRM primers should be just fine for reloading 357 Magnum cases. If you want to be really cautious, as I am, and if you are at or near a maximum safe load, back off the powder charge a few tenths of a grain and work up.
 
You don't really need SRM primers as normal SR primers will provide all the pressure safety you need. I have always used ordinary SR primers in all sorts of handgun loads, even 9x23 Win loads which generate chamber pressures in the 50Kpsi range, without any failures. Of course if you feel safer using SRM primers, there is no reason not to use them if they fire with 100% reliably in whatever guns you are using them in.
 
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Humm I was taught from our engineering people that Mag primers not specific to that ctg causes different pressure curves dependent on Powder as in Over pressure...then again what do they know they are just the Chem Engineer Folks at NOS Indian Head when I worked in the Metrology lab... some of our folks came from major powder manufactures. Im thinking the advice above is Reckless. BTW the difference in SR and Mag SR or LR and Mag LR etc has little to do with Primer Anvil or "Hard or soft" Its the Primer Base Chemicals which can and will change the Weapons barrel pressure. WA Y WAY to much bad info. I would add a Disclaimer on ANY reloading info given here to keep the site from Suite when someone hurts themself with bad advice.
 
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Mrnurse said:
Humm I was taught from our engineering people that Mag primers not specific to that ctg causes different pressure curves dependent on Powder as in Over pressure...then again what do they know they are just the Chem Engineer Folks at NOS Indian Head when I worked in the Metrology lab... some of our folks came from major powder manufactures. Im thinking the advice above is Reckless. BTW the difference in SR and Mag SR or LR and Mag LR etc has little to do with Primer Anvil or "Hard or soft" Its the Primer Base Chemicals which can and will change the Weapons barrel pressure. WA Y WAY to much bad info. I would add a Disclaimer on ANY reloading info given here to keep the site from Suite when someone hurts themself with bad advice.
Click to expand...


That's why I said I was cautious, especially if the current load is at or near maximum safe. Back off the charge a little and work up. I'd say the same advice goes for just switching primer brands.
 
Hmmmm? With all these dire warnings about getting hurt by switching primers in handloads???. Getting hurt, really?? I wonder why primer mfgs state that the only difference in SR and SPMPs is cup hardness. I would like to see REAL evidence where switching primers in any handload sent pressure spiraling to catastrophic levels causing injury from a blowup.
 
alwslate said:
Hmmmm? With all these dire warnings about getting hurt by switching primers in handloads???. Getting hurt, really?? I wonder why primer mfgs state that the only difference in SR and SPMPs is cup hardness. I would like to see REAL evidence where switching primers in any handload sent pressure spiraling to catastrophic levels causing injury from a blowup.
Click to expand...
We most likely won't.

Any 'blowups' we hear about are most likely be due to OTHER reloading mistakes or negligence and not due to something as simple as substituting primers.

This is an old, and often repeated thread on most gun related forums and will probably never be 'put to rest'.
 
Well to the post above from the gent in Indy I would ask... Sir Can you tell me the Compound mixture ( In stoichiometry Terms ) for SP and SPM or any other Sir....you are quite wrong in your advice.... Hard or Soft Primers has to do with Anvil thickness and primer material. Expelling gas with false info gets people dead. Oh BTW I have seen first hand reloaders that over charge, or use the wrong powders and primers several times and Applied a Tourniquet to the left hand that had 3 fingers blown off from a gent and his M1a in 2004 ...Im a RN and Combat medic, a Engineer in Aerospace and Materials.BTW spent 3 years Indian Head MD NOS and 2 years Beretta 1985-7 setting up the M9 Line. USE POWDER AND PRIMER MANUFACTURE INFO ONLY TO RE-LOAD.
 
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I've been using SR and SP primers as being virtually interchangeable for years, long before the current shortage. As a former sponsored competitive shooter for Hornady, I had a ton of insider info available. Of course it varies by brand, but for the most part standard small pistol, and small pistol magnum, and small rifle standard and magnum are pretty much the same thing. I've used whatever of whichever one was available with absolutely no perceptible differences for years. Only caveat is that CCI small pistol seem to have pretty hard cups, and I've had some misfires in my 5 screw K38, with it's light hammer spring, and amazing trigger pull.
 
No I am not knowledgeable as to the specific chemistry of primers. But we are talking about primers not blasting caps that are going to detonate a powder charge and blow up a gun. I want to see real evidence of a blown up gun loaded with any full charge load in the .357 magnum at even top pressure of 35,000 psi that blew up from the ONE variable of ANY primer that could fit in the case other than the specified being used. With this kind of nonsense being bandied about today it’s no wonder that their are so many handloaders that are scared to load anything but squibs. Most quality guns today have a 100% minimum safety factor as to excessive pressure. So let’s see ONE REAL case of lost fingers caused by primer substitution. Just ONE !
 
Ive got 2000 Remington 6 1/2 primers Ive been using in lieu of small pistol magnum primers. Ive seen no change in accuracy of loads, or any pressure signs. Actually, seems like the loads are bit cleaner and the brass just falls out of the chamber.
 
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