magnum primers

WillieB · October 21, 2009, 06:59 AM

Is using magnum small pistol primers safe for 38 Special target loads (2.7 grs. Bullseye; 148 gr semi-wadcutter).

totalloser · October 28, 2009, 01:14 AM

Magnum primers use thicker brass to survive more pressure, and sometimes will be hard enough (from the thickness) to not fire in firearms designed for standard primers. I believe they are also a little hotter to light off slower burning powders used in magnum loads.

What I have read (on forums-take with a grain of salt!!!) is that you can use them, but should work your load up again as the hotter primer likely will raise pressures a bit, and so a lighter powder charge may be in order. But the harder primer may still cause misfire issues depending on the firing pin or hammer spring of the firearm.

I have never used magnum primers on non-magnum loads, so hopefully someone more experienced will chime in on this matter. Welcome to The Firing Line!

margiesex · October 28, 2009, 08:51 AM

To follow up on the above, I've never used mag. primers in a .38 case. I used to load Bullseye 2.5 in the loads you mention. No need for a mag. primer.

However, I do use a magnum primer on the .358 load I shoot - 158 Gr. JSP pushed by 15 grains of 2400. I feel you need it for the larger amount of powder to help it all burn better.

God bless.

Margiesex

And remember: Hug your God and your guns - 'cause he's coming for them both, and soon!

Foxbat · October 28, 2009, 09:13 AM

I recently checked the effect of magnum versus regular primers and found it too close - normal velocity variations would swamp the differences between the two primers. At least that was true of the CCI primers. Just to be safe, you might want to back up some.

Now, the effect of course may be different for different powders, charge size and case, so as a safe rule, go back 10%, then move up in steps.

Jector · October 28, 2009, 12:13 PM

Well I tested some. This is not at all scientific and may be useless since the primers were different manufacturers but I'll post what I found for your entertainment.

The test:

I used Speer plastic bullets that are designed to be used with a large pistol primer only, no powder charge.

I fired several shots through my chronograph and here's what I got. Sorry, I didn't have any Large Pistol Magnum primers.

Large pistol primer - Federal 150 - average 539 fps
Large rifle primer - Remington No. 9 1/2 - Average 533 fps
Large rifle magnum primer - Federal match - Average 678 fps

So in this example the magnum was substantially hotter and the rifle vs pistol were nearly identical.
Note, I had to modify the gun to get it to ignite the rifle primers, they are defiantly harder.

October 21, 2009, 06:59 AM	#1
WillieB Junior Member Join Date: January 1, 2009 Posts: 10	magnum primers Is using magnum small pistol primers safe for 38 Special target loads (2.7 grs. Bullseye; 148 gr semi-wadcutter).

October 28, 2009, 01:14 AM	#2
totalloser Senior Member Join Date: October 19, 2007 Location: Fort Bragg, CA Posts: 679	Magnum primers use thicker brass to survive more pressure, and sometimes will be hard enough (from the thickness) to not fire in firearms designed for standard primers. I believe they are also a little hotter to light off slower burning powders used in magnum loads. What I have read (on forums-take with a grain of salt!!!) is that you can use them, but should work your load up again as the hotter primer likely will raise pressures a bit, and so a lighter powder charge may be in order. But the harder primer may still cause misfire issues depending on the firing pin or hammer spring of the firearm. I have never used magnum primers on non-magnum loads, so hopefully someone more experienced will chime in on this matter. Welcome to The Firing Line! __________________ You only truly believe in freedom if you believe in the freedom of those you disagree.

October 28, 2009, 08:51 AM	#3
margiesex Senior Member Join Date: June 5, 2009 Location: Levittown, PA Posts: 210	I haven't had the need... To follow up on the above, I've never used mag. primers in a .38 case. I used to load Bullseye 2.5 in the loads you mention. No need for a mag. primer. However, I do use a magnum primer on the .358 load I shoot - 158 Gr. JSP pushed by 15 grains of 2400. I feel you need it for the larger amount of powder to help it all burn better. God bless. Margiesex And remember: Hug your God and your guns - 'cause he's coming for them both, and soon!

October 28, 2009, 12:13 PM	#5
Jector Member Join Date: September 24, 2009 Posts: 85	Magnum vs. regular Well I tested some. This is not at all scientific and may be useless since the primers were different manufacturers but I'll post what I found for your entertainment. The test: I used Speer plastic bullets that are designed to be used with a large pistol primer only, no powder charge. I fired several shots through my chronograph and here's what I got. Sorry, I didn't have any Large Pistol Magnum primers. Large pistol primer - Federal 150 - average 539 fps Large rifle primer - Remington No. 9 1/2 - Average 533 fps Large rifle magnum primer - Federal match - Average 678 fps So in this example the magnum was substantially hotter and the rifle vs pistol were nearly identical. Note, I had to modify the gun to get it to ignite the rifle primers, they are defiantly harder.

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October 28, 2009, 09:13 AM	#4
Foxbat Senior Member Join Date: January 13, 2008 Posts: 367	I recently checked the effect of magnum versus regular primers and found it too close - normal velocity variations would swamp the differences between the two primers. At least that was true of the CCI primers. Just to be safe, you might want to back up some. Now, the effect of course may be different for different powders, charge size and case, so as a safe rule, go back 10%, then move up in steps.