Substituting magnum primers?

[Jim Watson]

9mm Para + 135 gr coated + HP38.
I chronographed with every primer I could lay hands on, SP, SR, SP magnum.
Seven out of eight were the same, within one standard deviation overlap.
Remington 1 1/2 SP standard was a little faster than the magnums and rifles and other SP.

Magnum LP gave somewhat higher velocity in .45 ACP than standard LP but I was shooting powderpuff loads with Bullseye.

[1986s4]

I've used 'em for years when standard primers are not available with zero issues and no difference noted. Recently I've been trying SR primers in .38 super, minor and major, again zero issues.

[TiroFijo]

A fex years back, I shot a couple thousand magnum primers (only thing I had at the time) in non magnum handgun calibers, loaded to normal pressures. No issues whatsoever.

[Jim Watson]

A guy here bought S&B SR for use in 9mm. Misfires are common; apparently they are harder than American SR. But he saved $3 a thousand, so now he has a longterm supply for his seldom shot AR.

[Trooper224]

He may or may not need magnum primers, depending upon the powder he's using. The use of magnum primers is dictated by the type of powder used, ie. burn rate, not whether or not the cartridge itself is a "magnum" (which many people consider the 10mm to be in all but name. Magnum primers burn longer, not necessarily hotter and are used with slower burning powders in order to achieve a more complete burn. There's a definition of magnum primers that you didn't ask for.

I stopped using magnum primers about two decades back because I found accuracy to be better without them. As for your friend using magnum primers: he shouldn't have a problem since the difference really isn't that great. If the primer sends his load over the red line, he has other issues that need addressing.

[deputyG23]

I picked up some Winchester small pistol magnum primers in '13 because standards were not available. Used them with WST powder and .38 and 9mm. No issues.

[Lester Polfus]

Thanks everyone.

This may actually prove interesting. Blue Dot has always given wide standard deviations in velocity. I've theorized that a magnum primer might settle that down a little bit. Guess we'll find out.