Standard primers or Magnum primers?

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RGVshooter

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I started to reload a batch of 357 magnums today and then I noticed that in my Hornady 9th edition manual lists Winchester small pistol magnum (WSPM) primers for all their loads they've listed & then I go in my Speer #14 and it only lists magnum primers for some powders and not others.

I found two similar loads in both manuals using the same powder yet the Hornady manual states small pistol magnum and speer for the same load just uses standard primers. Again, in the Speer manual, some loads get the magnum primer and others don't meanwhile the Hornady book, all loads get the magnum primer...

I have a whole case of Winchester WSP primers, I'm just gonna use them... here's the load data I'm using today.

158 gr. LSWC HP

3.8 gr. TiteGroup

OAL 1.590"

I think in this case, I'm fine using standard primers.
 
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Going by that reload data you posted, that isn't a magnum charge, so the small pistol primers would be what you should be using. When you start to get into the high charges of H-110 /win 296 than you need a small pistol magnum primer.
 
Magnum primers are used for slower, hard to ignite powders, aka "Magnum powders". The data in the manuals are just reports of what the lab techs used and the results, not hard and fast formula. Also components vary from lot to lot and one of the reasons reloading manuals differ in their data. Your load sounds fine.

I have used mostly standard primers in my Magnums with the exception of when I'm using H110/W296. I've also read some use magnum primers with 4277, but I haven't tried that powder...
 
Double base ball powders have more deterrent coatings than single base powders to help control the burn rate and lower peak flame temperature.

The deterrent coatings make the double base powders harder to light off and all the older manuals show the use of magnum primers.

Food for thought, Remington ran Lake City Army Ammunition Plant from 1941 until 1982. And they used the Remington 7 1/2 primer for all the 5.56 ammunition produced. They also loaded the 5.56 ammunition with Winchester ball powders.

Now look at the photos below of different type primers and pay attentiohttp://www.6mmbr.com/primerpix.htmln to the Remington 7 1/2 primer they used to light off Winchester double base ball powders.

Primer Flash Test Photos
 
Last edited:
I have posted this note before. SPEER RELOADING MANUAL #14, Caliber: 357 Magnum, page 892, Do not use magnum primers with 2400 or VihtaVuori N110 loads shown here or high pressure will result.
 
Your load using Titegroup is fine with regular primers.You'd be surprised at the number of guys who walk up to me and say they use magnum primers just because the word is stamped on the brass.
I usually take a few minutes to explain them that it is the type of powder and not what is stamped on the brass that is the gauge by which the use of mag primer is mandatory and for my part,I use Mag primers with such slow burners as H110/W296 and IMR 4227.There might be a few others but I don't use them.
Qc
 
Qc Pistolero said:
I usually take a few minutes to explain them that it is the type of powder and not what is stamped on the brass that is the gauge by which the use of mag primer is mandatory and for my part,I use Mag primers with such slow burners as H110/W296 and IMR 4227.There might be a few others but I don't use them.
Qc
Click to expand...

I was going by the load data in my Hornady 9th edition reloading manual & comparing it to my Speer #14 book. The Hornady called for Magnum primers in all the loads whereas the Speer only listed magnum primers for certain powders. I thought that was interesting.

Although most loads I went by off the Hornady manual were very good, their loads seem to be more "conservative" when compared to the same loads listed in Speer's book.
 
I only use Mag primers when the load calls for a "Ball Powder"...........

Flake or extruded powders do well with a standard primer.

Since Winchester is a ball powder company, both their std and mag primers will work for all powders.
 
Handloader (the magazine) had an article awhile ago that magnum primers cause an increase in some powders (as noted above). It was an extensive article with a lot of data. Generally only a concern if loading towards the maximum.

I always use the non magnum primers in my 357 calibers. Never had a problem.
 
Well standard primers for that load is just fine. I load 3.4 in 38 special with that powder and a 158 grain SWC. As for H110 I've used standard CCI primers and loads and groups were fine. H110 in a .22K hornet with standard pistol primers groups better than rifle primers or mag primers. I've also used standard primers before in the 44 Mag as well. Now I know some may say not so but it works. During the primer shortage I was using Tula primer but my go to primers are CCI. Which by the way I have several thousand stored. And with this said and shooting and reloading since 1979 a lot of shooting has taken place.
 
I use the correct primer that’s required for that powder. For large pistol primers I use Winchester primers it covers standard and magnum primers.

In rifles there is three different large rifle primers. A standard primer, a military thicker wall primer 1 1/2 Times hotter over standard. Them the magnum primer is 3 Times hotter over standard. This means a hotter chamber pressure too. You must read the fired primer in the case too for higher pressure.
 
Pray tell, exactly where did you find this information? And what does "Hotter" mean?

"In rifles there is three different large rifle primers. A standard primer, a military thicker wall primer 1 1/2 Times hotter over standard. Them the magnum primer is 3 Times hotter over standard. This means a hotter chamber pressure too. You must read the fired primer in the case too for higher pressure."
 
Speer used to list magnum primers only for the powders that were hard to ignite, slow ball powders. Nowadays most "Magnum cartridges" will list a magnum pistol primer in the data.

I wrote Hodgdon a few years ago and asked them why they used a magnum primer with HP-38 in their .357 Magnum load data and was told they use a magnum primer with all their magnum load data. The reason, there are reloaders who don't pay good attention to the primer used and could assume if it's a magnum cartridge it must use a magnum primer. If they use a standard primer and the loader substitutes a magnum primer it could cause an over pressure problem.

I'm not sure if that's true but it's what they told me. I just figured they were being lazy and it was easier to use just one primer when testing all the powder/bullet combination in that cartridge.
 
Magnum does not mean you need a mag primer. I only use them for H100/W296 loads in my magnums. Everything else gets std primers, regardless of the book.
 
Nevada Ed said:
I only use Mag primers when the load calls for a "Ball Powder"...........

Flake or extruded powders do well with a standard primer.

Since Winchester is a ball powder company, both their std and mag primers will work for all powders.
Click to expand...

You do not need a mag primer to ignite small charges of ball powder. All my 9/40 minor loads run fine on std primers. Going to a mag primer opened groups a bit with no appreciable gain in vel thus pressures.
 
Well I will be working up some bowling pin loads shortly.
.357 mag 180 gr over 2400 and HS6, maybe something else if I have any partial cans laying around. Think I have some 4756 left over from my 38 super open days.
Anyway will use magnum and standard and see what the chrono says.
 
Joe4d said:
Well I will be working up some bowling pin loads shortly.
.357 mag 180 gr over 2400 and HS6, maybe something else if I have any partial cans laying around. Think I have some 4756 left over from my 38 super open days.
Anyway will use magnum and standard and see what the chrono says.
Click to expand...

I only use magnum primers with W296/H110, HS-6/W540 and HS-7/W571 when I finds some. Everything else gets a standard primer. I won't know about W572 until I do some tests with both primers. The ES, SD and MV will decide which primer I will use.
 
Hold the phone....

I read an article last night, but I didn't mark it, daggum it. But the jist of it was that the lightest primer charge to effectively light the powder will give the smallest standard deviation. Though I use standard and magnum primers, I've always felt that a slight reduction in powder could level it. This info says that if narrow standard deviation is important to you, you shouldn't use a larger primer than specified for a load.

Being a recreational target shooter and not a competitor, SD doesn't affect me much, but if you are a competing shooter, you may want to look into this.
 
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