Magnum Primers vs Standard Primers

Dr Killdeer · February 7, 2010, 07:59 AM

Primers are getting scarce in my neck of the woods. Since regular large rifle primers are not available right now, I thought about buying large rifle magnum primers instead. I know they’ll go BANG, but I don’t know if it’s a good idea to make the substitution.

I’ll bet somebody out there has done this before! Any help will be greatly appreciated.

Uncle Buck · February 7, 2010, 08:07 AM

Everything I have read says you can do it, but you must reduce the starting load to the minimum and work your way back up.

I was reloading some .38 Special last night and saw that I accidentally picked up 1K of small pistol magnum primers, instead of the small pistol.

Guess I will hold on to them and have to make a run back to the store and get more. I have read here on the forum that primers will last for years, so no hurry to use them.

SwampYankee · February 7, 2010, 08:15 AM

I have 4K of magnum large rifle primers on hand (these are Winchesters, the hottest of the magnums). I've been using them in every rifle I have of .308 and .303. They are fine, I have had no problems. However, I never load to maximum- frequently I am below the recommended minimum starting charges because that is where I am finding the best accuracy. For example, I am putting 37 g of H4895 behind 168 g match .308's. The starting charge is something like 40 g? With the speeds I am getting, Quickload thinks my pressures are in the 33k psi range.

I'm not killing anything so the velocity is not that important to me and frankly, I'm not a fan of beating myself up with recoil if I can avoid it.

I picked these primers up about 6 months ago, they were dusty and the seller gave them to me for $16 a box, he wasn't sure if they were any good. My guess is they had been sitting around since the mid-90's. I've been through 600 of them and they work fine...

DiscoRacing · February 7, 2010, 09:02 AM

i load with mag primers for .308, .270, 30.06 and 7mm

Nevmavrick · February 8, 2010, 07:11 AM

I've loaded a ...load of ammo with magnum primers over the years, and many of them went over the chronograph, comparing with the same load with standard primers. The usual result was the variation was higher, and the average velocity was lower, indicating erratic pressures. That was with faster single-base powders, like 3031, 4064, and 4320 in standard rounds like .300 Sav., 7x57 Mauser, .250/3000.
Using slower single-base or Ball with lots of deterrent the Mag primer comes into it's own. THAT's what they're made for. Just reduce the load and pray that primers start becoming more readily available.
Have fun,
Gene

Snobal · February 8, 2010, 09:37 AM

My chronograph has provided hours of entertainment.

I have found more variation between "lots" of primers than between "Mag" vs "Standard" primers.

I quit loading to "Max" levels in the 1970's when I found my best accuracy with acceptable velocity was normally well below maximum pressures.

With some loads I get less shot-to-shot velocity variation with standard primers, with other loads - magnum primers give better results. My chronograph don't care what you shoot across it --- it just gives the velocity. So I use whatever combination of components that gives the best groups.

By the way, I have ammo and primers from the 1960's/1970's that still works just fine.

JMHO

Dr Killdeer · February 8, 2010, 01:41 PM

That’s great news! I’ll start off real easy with the magnum primers. I rarely use maximum loads anyway, because in the past I could never get them to print beyond 100 yards.

Many thanks guys!

crimsondave · February 8, 2010, 02:02 PM

I've used mag primers in IMR4350 before in a pinch and it did not make much difference. However, IMR4350 is a slow powder. If you load a faster powder it may screw up your groups.

February 7, 2010, 07:59 AM	#1
Dr Killdeer Senior Member Join Date: August 22, 2009 Location: Newburgh, NY Posts: 127	Magnum Primers vs Standard Primers Primers are getting scarce in my neck of the woods. Since regular large rifle primers are not available right now, I thought about buying large rifle magnum primers instead. I know they’ll go BANG, but I don’t know if it’s a good idea to make the substitution. I’ll bet somebody out there has done this before! Any help will be greatly appreciated. __________________ Man is the only animal on the planet that is capable of saying "I'm sorry." Further, he's the only one who creates the need to say it.

February 7, 2010, 08:07 AM	#2
Uncle Buck Senior Member Join Date: June 21, 2009 Location: West Central Missouri Posts: 2,592	Everything I have read says you can do it, but you must reduce the starting load to the minimum and work your way back up. I was reloading some .38 Special last night and saw that I accidentally picked up 1K of small pistol magnum primers, instead of the small pistol. Guess I will hold on to them and have to make a run back to the store and get more. I have read here on the forum that primers will last for years, so no hurry to use them. __________________ Inside Every Bright Idea Is The 50% Probability Of A Disaster Waiting To Happen.

February 8, 2010, 01:41 PM	#7
Dr Killdeer Senior Member Join Date: August 22, 2009 Location: Newburgh, NY Posts: 127	That’s great news! I’ll start off real easy with the magnum primers. I rarely use maximum loads anyway, because in the past I could never get them to print beyond 100 yards. Many thanks guys! __________________ Man is the only animal on the planet that is capable of saying "I'm sorry." Further, he's the only one who creates the need to say it.

February 7, 2010, 08:15 AM	#3
SwampYankee Registration in progress Join Date: November 1, 2008 Location: I can be found on a number of other forums. Posts: 1,333	I have 4K of magnum large rifle primers on hand (these are Winchesters, the hottest of the magnums). I've been using them in every rifle I have of .308 and .303. They are fine, I have had no problems. However, I never load to maximum- frequently I am below the recommended minimum starting charges because that is where I am finding the best accuracy. For example, I am putting 37 g of H4895 behind 168 g match .308's. The starting charge is something like 40 g? With the speeds I am getting, Quickload thinks my pressures are in the 33k psi range. I'm not killing anything so the velocity is not that important to me and frankly, I'm not a fan of beating myself up with recoil if I can avoid it. I picked these primers up about 6 months ago, they were dusty and the seller gave them to me for $16 a box, he wasn't sure if they were any good. My guess is they had been sitting around since the mid-90's. I've been through 600 of them and they work fine...

February 7, 2010, 09:02 AM	#4
DiscoRacing Senior Member Join Date: December 19, 2008 Location: milton, wv Posts: 3,640	i load with mag primers for .308, .270, 30.06 and 7mm

February 8, 2010, 07:11 AM	#5
Nevmavrick Senior Member Join Date: January 2, 2010 Location: Sparks, Nevada, near Reno Posts: 183	I've loaded a ...load of ammo with magnum primers over the years, and many of them went over the chronograph, comparing with the same load with standard primers. The usual result was the variation was higher, and the average velocity was lower, indicating erratic pressures. That was with faster single-base powders, like 3031, 4064, and 4320 in standard rounds like .300 Sav., 7x57 Mauser, .250/3000. Using slower single-base or Ball with lots of deterrent the Mag primer comes into it's own. THAT's what they're made for. Just reduce the load and pray that primers start becoming more readily available. Have fun, Gene

February 8, 2010, 09:37 AM	#6
Snobal Senior Member Join Date: January 4, 2009 Location: Arizona Wilderness Posts: 121	My chronograph has provided hours of entertainment. I have found more variation between "lots" of primers than between "Mag" vs "Standard" primers. I quit loading to "Max" levels in the 1970's when I found my best accuracy with acceptable velocity was normally well below maximum pressures. With some loads I get less shot-to-shot velocity variation with standard primers, with other loads - magnum primers give better results. My chronograph don't care what you shoot across it --- it just gives the velocity. So I use whatever combination of components that gives the best groups. By the way, I have ammo and primers from the 1960's/1970's that still works just fine. JMHO

February 8, 2010, 02:02 PM	#8
crimsondave Senior Member Join Date: September 30, 2009 Location: North Augusta, SC Posts: 490	I've used mag primers in IMR4350 before in a pinch and it did not make much difference. However, IMR4350 is a slow powder. If you load a faster powder it may screw up your groups.