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magnum primers in standard loads?

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July 27, 2022, 03:48 PM
357p239
magnum primers in standard loads?
I have Winchester SPM primers. Can I use these in place of Winchester SP primers? What do you think. Any worries about increased pressures or anything
July 27, 2022, 04:07 PM
Flash-LB
As long as you're not using maximum loads, you'll be fine.

A lot of people I know have been doing this in the last couple of years with no problems whatsoever.

Here's a good video explaining the whole thing.

This message has been edited. Last edited by: Flash-LB,
July 29, 2022, 04:24 PM
RoverSig
My experience is the same. I use them in place of standard small pistol primers with no ill effects. I do not load any of my shells close to the max pressure, though.

Indeed, the thought just entered my head that you might get better (more uniform) ignition and powder burn in very light loads if you use magnum primers.
July 29, 2022, 10:26 PM
357p239
Thanks for the advise, guys. I'll give it a try.
August 11, 2022, 12:13 PM
cas
The answer is… who knows and, you and I certainly have no idea what’s really happening.

The owner of a well known “boutique” ammo company told us years ago that pressure can go up, stay the same and he’s even seen it go down with magnum primers. So who knows.


_____________________________________________________
Sliced bread, the greatest thing since the 1911.

August 11, 2022, 03:20 PM
Flash-LB
quote:
Originally posted by cas:
The answer is… who knows and, you and I certainly have no idea what’s really happening.

The owner of a well known “boutique” ammo company told us years ago that pressure can go up, stay the same and he’s even seen it go down with magnum primers. So who knows.



You didn't watch the Video did you? They measured pressure in the testing.
August 12, 2022, 10:32 AM
Jim Watson
I saw NO difference among six different small primers in 9mm with HP38. Well, the Remington small pistol was a little faster than other brands whether pistol, magnum, or rifle.

Large primers in .45 with Bullseye did make a difference, so when my bullet order comes in and I start loading .45 Small with small pistol magnum, I will chronograph a series.
August 15, 2022, 02:15 PM
cas
quote:
Originally posted by Flash-LB:
quote:
Originally posted by cas:
The answer is… who knows and, you and I certainly have no idea what’s really happening.

The owner of a well known “boutique” ammo company told us years ago that pressure can go up, stay the same and he’s even seen it go down with magnum primers. So who knows.


He tested one thing. And I mentioned a man who's company tests a whole array of loads across many many different calibers.

????

You didn't watch the Video did you? They measured pressure in the testing.

September 18, 2022, 08:31 PM
jaysingletary
I used them in my light plinking loads for years with no problems. I’ve also chosen to forgo state mandated psychiatric treatment in favor of self administered electronic shock therapy.
October 20, 2022, 05:04 PM
jhe888
The conventional wisdom was that magnum primers could increase pressure. I don't know.

If you are at or close to maximum loads, any change in components should probably cause you to drop back on your powder charge a little and work your way up to what gives you what you want.




The fish is mute, expressionless. The fish doesn't think because the fish knows everything.
January 27, 2023, 08:31 PM
Rodfac
quote:
As long as you're not using maximum loads, you'll be fine.
Yep, but your accuracy my differ somewhat. Rod


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January 28, 2023, 07:26 AM
shovelhead
I’ve been wondering about this also. A friend has been acquiring reloading components and primers have been the hangup. I recently was given 1000 CCI SMP’s together with a set of 30-06 dies that I passed along to him.

The primers are probably circa 1980-90 era, box looks dry, hopeful that they are still good.


-------------------------------------——————
————————--Ignorance is a powerful tool if applied at the right time, even, usually, surpassing knowledge(E.J.Potter, A.K.A. The Michigan Madman)
January 28, 2023, 08:32 AM
Flash-LB
quote:
Originally posted by shovelhead:
I’ve been wondering about this also. A friend has been acquiring reloading components and primers have been the hangup. I recently was given 1000 CCI SMP’s together with a set of 30-06 dies that I passed along to him.

The primers are probably circa 1980-90 era, box looks dry, hopeful that they are still good.


Unless they've been wet, they will be. I've still got some that are from the early 1970s that are good.
May 13, 2023, 06:50 PM
huskerlrrp
I used magnum primers all the time for lower standard deviations and more accurate loads. It usually takes 0.2 grains less for the same speeds.