Standard Rifle Primers in Magnum Cartridge

3StrikesNC · November 1, 2009, 09:50 PM

Okay, I just reloaded some 7mm STW cases with 65 grains of IMR 4350 and 150 grain Combined Technology Ballistic Silvertip bullets. My only issue is when I was done I realized I had used Standard Rifle Primers instead of Magnum Rifle Primers (stupid me

).

Will this be an issue?

I also primed some cases which I had planned to use Reloader 22 and some Hornady 175 grain spire points. Any issue here?

Thanks.

**Unclenick** · November 1, 2009, 10:43 PM

The loads will fire, but are likely to have wider velocity variance than would be the case with standard primers. The job of the magnum primer is to raise the pressure of the case to make the powder start and sustain its burn more easily. That helps when the case is not full, as is the case with your 4350 load. If you raise the muzzle before firing to get the powder over the primer, that can help.

3StrikesNC · November 2, 2009, 09:03 PM

Thanks.

Guess I just blew it. I'll just use them for 100 yd paper. Good thing I didn't do them all this way.

reloader28 · November 2, 2009, 10:41 PM

You could shoot them up for practice but personally I hate wasting the stuff. Why dont you just pull the bullets and start over? Or maybe pull them and just add a grain of polyfill over the powder to keep it in place. That helps too.

GeauxTide · November 3, 2009, 08:47 AM

I'd pull 'em. Cases are already prepped, and repriming is easy.

elwaynum1 · November 3, 2009, 02:24 PM

I also have a question regarding magnum primers. (sorry to hijack the thread)..I am loading about 55 grains of IMR 4831 for 7mm Rem mag with 150gr Sierra SBT's, but have been using standard large rifle primers. Will changing to magnum primers make a difference? And, when should I or shouldn't I opt for magnum primers?

Ifishsum · November 7, 2009, 11:12 PM

I think more about the powder I'm using than the actual cartridge when making a primer choice. Ball powders can be harder to ignite so I tend to use magnum primers with them, and standard primers when using extruded powders - regardless of whether the cartridge is a "magnum" or not. I've never used magnum primers with 4350, they're just not necessary.

Elwaynum1: There's no reason to think that you'll gain anything from a good load simply by switching to magnum primers. If you've worked up the load using standard primers and you want to try magnums, you should drop the charge weight by a little bit and work them back up again. Anything else is taking a shot in the dark (and an unnecessary risk).

November 1, 2009, 09:50 PM	#1
3StrikesNC Senior Member Join Date: October 22, 2007 Location: in a house Posts: 473	Standard Rifle Primers in Magnum Cartridge Okay, I just reloaded some 7mm STW cases with 65 grains of IMR 4350 and 150 grain Combined Technology Ballistic Silvertip bullets. My only issue is when I was done I realized I had used Standard Rifle Primers instead of Magnum Rifle Primers (stupid me ). Will this be an issue? I also primed some cases which I had planned to use Reloader 22 and some Hornady 175 grain spire points. Any issue here? Thanks.

November 1, 2009, 10:43 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	The loads will fire, but are likely to have wider velocity variance than would be the case with standard primers. The job of the magnum primer is to raise the pressure of the case to make the powder start and sustain its burn more easily. That helps when the case is not full, as is the case with your 4350 load. If you raise the muzzle before firing to get the powder over the primer, that can help. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

November 2, 2009, 09:03 PM	#3
3StrikesNC Senior Member Join Date: October 22, 2007 Location: in a house Posts: 473	Thanks. Guess I just blew it. I'll just use them for 100 yd paper. Good thing I didn't do them all this way.

November 2, 2009, 10:41 PM	#4
reloader28 Senior Member Join Date: October 13, 2009 Location: nw wyoming Posts: 1,061	You could shoot them up for practice but personally I hate wasting the stuff. Why dont you just pull the bullets and start over? Or maybe pull them and just add a grain of polyfill over the powder to keep it in place. That helps too.

November 3, 2009, 08:47 AM	#5
GeauxTide Senior Member Join Date: April 20, 2009 Location: Helena, AL Posts: 4,424	I'd pull 'em. Cases are already prepped, and repriming is easy.

November 3, 2009, 02:24 PM	#6
elwaynum1 Member Join Date: October 9, 2009 Location: Texas Posts: 85	I also have a question regarding magnum primers. (sorry to hijack the thread)..I am loading about 55 grains of IMR 4831 for 7mm Rem mag with 150gr Sierra SBT's, but have been using standard large rifle primers. Will changing to magnum primers make a difference? And, when should I or shouldn't I opt for magnum primers?

November 7, 2009, 11:12 PM	#7
Ifishsum Senior Member Join Date: September 15, 2005 Location: Oregon Posts: 1,033	I think more about the powder I'm using than the actual cartridge when making a primer choice. Ball powders can be harder to ignite so I tend to use magnum primers with them, and standard primers when using extruded powders - regardless of whether the cartridge is a "magnum" or not. I've never used magnum primers with 4350, they're just not necessary. Elwaynum1: There's no reason to think that you'll gain anything from a good load simply by switching to magnum primers. If you've worked up the load using standard primers and you want to try magnums, you should drop the charge weight by a little bit and work them back up again. Anything else is taking a shot in the dark (and an unnecessary risk).