Does anyone know what kind of velocity hit (fps) one would take by not using small pistol magnum primers and instead just using small pistol primers in 357 Magnum?
Cant comment on the specific loss in velocity I did notice wildly changing velocities. I find magnum primers are more consistent and more stable.
It would depend a lot on which powder you are using
That jives with a report I read, where 2400 powder reached max pressure with a lower charge, and had a resulting lower velocity when using magnum primers. Max performance was with standard primers.Definitely powder dependent. 2400 doesn't require magnum primers & my .41 shot erratically with them. Switched to standard primers & it shot great.
That jives with a report I read, where 2400 powder reached max pressure with a lower charge, and had a resulting lower velocity when using magnum primers. Max performance was with standard primers.
Performance differences between regular and magnum primers will be dependent on the powder used.
I don't give reloading advice or load formula's on this forum any longer. Too many idiots that will argue with a brick wall to waste time on. If you really want to know, give it a try and post results or consult a reputable manual...
For sure, powders all burn at different rates and different temperatures. Local outside air temperature, elevation, etc also play into the mix. I asking in terms of generalities, if there is such a thing.
Primarily, I was wondering if the manufacturers had published any data or if anyone had done their own tests with different powders to make a somewhat definitive statement on the matter.
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That pretty much sums it up.Anecdotally I can tell you:
1) magnum primers are generally match up with certain powders, not certain cartridges.
2) Using a standard primer when a magnum is called for can result in poor ignition, incomplete burn, erratic velocity
3) using a magnum primer when a standard is specified can have any result from no change to unexpected pressure spikes.
4) SRP is basically equivalent to SPM as long as your gun will set them off.
5) Whatever you're doing, start low and work up.
Sorry I can't be definitive but I don't think that's possible outside of a lab.
Very cool. Thank you for this detailed share.OK, this question was a perplexing one and so I decided to test it out for myself to see what I came up with. I tried to be as exacting as I could be without completely going down a rabbit hole, i.e., I did not weigh and sort every projectile.
I started with:
- brand new virgin Starline 357 brass
- 24 grains of Alliant 2400 powder (each round individually weighed on a RCBS Chargemaster Combo)
- Because I wasn't using a maximum powder charge, I tested three different types of CCI Primers: CCI small pistol primers, CCI small magnum pistol primers and just for grins CCI small rifle primers.
My test pistol was a 4 inch Rossi 357 Revolver. My chronograph was a Competition Electronics ProChrono Digital Chronograph with Digital Link to upload the data to my cell phone in a PDF format.
DISCLAIMER: This is my load data utilizing my components, pistol, chronograph and reloading skills. These are my results and your results might vary. Do not use this loading data or the results as a definitive guide on what you should reload. You alone, are responsible for what YOU reload.
Here are the results and just for reference, the last chronograph results you will see is for factory Federal 357 158 Gr JSP ammunition.
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24gr of 2400 in a .357?!?!? Will that even fit in the case? I don't even know of a .41 load that calls for that much 2400. Did you mean 14gr?