WSPM primer for standard 9mm load?

twins · April 29, 2011, 05:59 PM

Made a mistake and picked up the Winchester Small Pistol Magnum (WSPM) primer instead of the regular WSP primer. Is it ok to use in standard load for 9mm Luger? Or do I have to go get the regular WSP primer?

Thanks.

Adamantium · April 29, 2011, 06:30 PM

Should you want to use the WSPM the only safe answer is to re-work your intended load from it's reduced charge and monitor for pressure signs.

Clifford L. Hughes · April 29, 2011, 06:32 PM

Twins:

At times I have used magnum primers in non magnum rifle and pistol calibers. However, I don't reload up to the maximun either. In rifles calibers with a large case capicity, like the 30/06, when using slow powders like 4831 a magnum primer is useful, but not necessary. I feel that with slow burning powders and the amount of powder compression required to seat the bullets that a magnum primer assures me of consistent ignation. What I'm saying is that case capicity, powder type and not the cartridge's name designation should be considered when selecting a primer. For instance, the 222 Rem. Mag is designated magnum but is it a magnum when is comes to selecting primers for loading it. Not hardley.

For piatol calibers if the powder charge is not maximun I don't think that you will experience problems. However, be for warned that the small capicity pistol cases and the faster burning powders that they require that you could get into trouble quick using maximun powder charges with magnum primers.

Semper Fi.

Gunnery Sergeant
Clifford L. Hughes
USMC Retired

zxcvbob · April 29, 2011, 06:45 PM

Years ago I started out reloading 9mm using only Federal small rifle primers. They work just fine, and SPM primers aren't really much different. They may (or may not) raise your pressures though, so if you are anywhere near a maximum load you need to back off towards a starting load and work it up again jus to make sure.

frumious · April 29, 2011, 07:05 PM

I have also used small pistol magnum primers with low-to-mid-range charges of Bullseye. No problems. I only did this because magnum was all that was available.

As others have said, if you are at max then back off before you use the magnum primers.

-cls

twins · May 3, 2011, 05:21 PM

Update on using the WSPM instead of WSP primers for standard 9mm Luger load.

Powder: Hodgdon Universal, loaded 4.0 to 4.4 grs with .1 gr increment. Max load is 4.5 grs.
Bullets: 115 gr Missouri RN & 115 gr Hornady XTP
Primer: Winchester Small Pistol Magnum
Case: Starline

Handguns: Hi-Point C9 Comp & S&W 5903

No issue with using the Magnum primer with these loads. Both handguns showed no signs of overpressure with 4.4 grs. The Hi-Point was very accurate with 4.2 grs while the S&W didn't group well until 4.4 grs. Will try 4.5 grs next time to see if there's a problem with pressure and see if I can get the S&W to group better.

April 29, 2011, 05:59 PM	#1
twins Senior Member Join Date: October 1, 2010 Posts: 393	WSPM primer for standard 9mm load? Made a mistake and picked up the Winchester Small Pistol Magnum (WSPM) primer instead of the regular WSP primer. Is it ok to use in standard load for 9mm Luger? Or do I have to go get the regular WSP primer? Thanks.

April 29, 2011, 06:32 PM	#3
Clifford L. Hughes Senior Member Join Date: February 24, 2011 Location: Southern Californis Posts: 795	Clifford L. Hughes Twins: At times I have used magnum primers in non magnum rifle and pistol calibers. However, I don't reload up to the maximun either. In rifles calibers with a large case capicity, like the 30/06, when using slow powders like 4831 a magnum primer is useful, but not necessary. I feel that with slow burning powders and the amount of powder compression required to seat the bullets that a magnum primer assures me of consistent ignation. What I'm saying is that case capicity, powder type and not the cartridge's name designation should be considered when selecting a primer. For instance, the 222 Rem. Mag is designated magnum but is it a magnum when is comes to selecting primers for loading it. Not hardley. For piatol calibers if the powder charge is not maximun I don't think that you will experience problems. However, be for warned that the small capicity pistol cases and the faster burning powders that they require that you could get into trouble quick using maximun powder charges with magnum primers. Semper Fi. Gunnery Sergeant Clifford L. Hughes USMC Retired Last edited by Clifford L. Hughes; April 29, 2011 at 06:44 PM.

April 29, 2011, 06:45 PM	#4
zxcvbob Senior Member Join Date: December 20, 2007 Location: S.E. Minnesota Posts: 4,720	Years ago I started out reloading 9mm using only Federal small rifle primers. They work just fine, and SPM primers aren't really much different. They may (or may not) raise your pressures though, so if you are anywhere near a maximum load you need to back off towards a starting load and work it up again jus to make sure. __________________ "Everything they do is so dramatic and flamboyant. It just makes me want to set myself on fire!" —Lucille Bluth

April 29, 2011, 06:30 PM	#2
Adamantium Senior Member Join Date: June 6, 1999 Location: El Paso, TX Posts: 1,021	Should you want to use the WSPM the only safe answer is to re-work your intended load from it's reduced charge and monitor for pressure signs.

April 29, 2011, 07:05 PM	#5
frumious Senior Member Join Date: May 13, 2009 Location: Carrollton TX Posts: 521	I have also used small pistol magnum primers with low-to-mid-range charges of Bullseye. No problems. I only did this because magnum was all that was available. As others have said, if you are at max then back off before you use the magnum primers. -cls

May 3, 2011, 05:21 PM	#6
twins Senior Member Join Date: October 1, 2010 Posts: 393	Update on using the WSPM instead of WSP primers for standard 9mm Luger load. Powder: Hodgdon Universal, loaded 4.0 to 4.4 grs with .1 gr increment. Max load is 4.5 grs. Bullets: 115 gr Missouri RN & 115 gr Hornady XTP Primer: Winchester Small Pistol Magnum Case: Starline Handguns: Hi-Point C9 Comp & S&W 5903 No issue with using the Magnum primer with these loads. Both handguns showed no signs of overpressure with 4.4 grs. The Hi-Point was very accurate with 4.2 grs while the S&W didn't group well until 4.4 grs. Will try 4.5 grs next time to see if there's a problem with pressure and see if I can get the S&W to group better.