To magnam or not to magnam primer?

R

RickCoop

New member
Hello. I need some experienced advice. I received a Lee die set for 38 Special / 357 magnam today (Christmas). So I started to look up load data for 158 gr bullet weight (I have copper plated Xtreme) . I looked up data in the Lyman 49th and I see that their load data reflects using a CCI 550 primer (magnam). I also looked at the Alliant 2014 reloaders guide for cross reference as I have both Bullseye and Unique and there I see CCI 500 (not magnam) primer. So, which one should I use or does it not matter?
I want to thank everyone in advance for their help. I am a fairly new reloader and this forum has been an invaluable resource for me.
 
IME, the requirement for a magnum primer is more dependent upon the powder than the load.
Unique or Bullseye, probably not.
H110/W296, yes.

BTW, "magnum", not "magnam"
 
Rick,

The technical advice is correct. H110/296, long favorites in magnum loads, have deterrent chemistry dating back to the 1960's, and it can actually push a bullet forward faster than the burn can keep up, expanding the volume the powder is trying to raise pressure in, so the pressure instead drops and the burn actually extinguishes, leaving a bullet stuck in the barrel. To prevent this, a magnum primer raises the start pressure so the early, difficult-to-sustain part of the burn is completed before the bullet gets too far forward. So that's all a magnum primer does in principle, though, in practice, a lot of them also make extra large showers of sparks to help ignition tunnel through the high deterrent concentration surface layer.

For Bullseye and Unique you can use the mildest primer made, and they both light and burn so fast that the bullet won't have gone very far by the time they've burned themselves out. So it will be just fine. Just be aware that pressure can change a little primer choice. For target loads the main hazard from this is excess bore fouling. If you get enough of that, then you can see pressures rise, but mostly it's just a cleaning nuisance.
 
Bullseye and Unique are my two favorite handgun powders just because they are simple and you can find several good loads for about every caliber and bullet weight of handgun ammo there is. I have never used Magnum Primers and never had a problem.
 
Very glad I found this thread. I also had questions regarding the appropriate time to use of standard and magnum. I have been using To Titegroup in my current 38/357 however I recently stumbled into a pound of H110 and have been looking for various info on making those loads. Good thread.
 
Beware of a recent lot of unplated WLR & WLRM primers that are undersize in diameter and fit loose in good primer pockets.

They forgot to allow for the diameter plating adds to metal!
 
A while back, I did a test on different primers I had on hand. I made some .22 Hornet gallery rounds loaded without powder and a .22 air rifle pellet as a projectile. The only propellant was the primer charge. Then I measured velocities with my chronograph.

CCI small rifle primers. Five shots.

304.5
318.2
332.3
384.2
299.9

Winchester small pistol primers.

363.3
280.6
369.7
275.9
351.9

Federal Magnum small pistol primers.

142.0
167.4
239.6
173.6
170.6

Go figure

The take away, a primer is a primer is a primer....not!
Don't assume standard primers are less powerful than magnum primers.
The consistancy of those CCI small rifle primers might explain why some of my most accurate loads used them.
A lot of loading manuals warn you to rework up a maximum load if you even change brands of primers or use a brand of primer different than listed in the load data. This data illustrates why.
 
I believe Lyman indicates primer grades based upon the cartridge rather than the powder choice (if it says "magnum"). I believe the powder company data is always the better example to follow regarding primer requirement. The exception that comes to mind is use of either small rifle primers or CCI Small pistol Magnum when loading the top end of 327 Federal Magnum (40k+ psi). That comes from Speer and the folks who created the cartridge, and it has less to do with ignition.
 
I have come to think that a primer does not just set the powder on fire, it also establishes the initial pressure in the chamber, which must be high enough to get the powder into its fast burn mode.
Set a pile of even the fastest burning smokeless powders on fire with a match and it burns amazingly slowly, unlike black powder which burns up in an instant, so quickly that there is no safe way to ignite it with a match.

I think the need to establish that initial pressure in the chamber is why the need for magnum primers is connected to case capacity, and why no one makes .50BMG brass with primer pockets that fit regular large rifle primers.
In large artillery, the 16 inch guns on battleships, there is a black powder igniting charge between the primer and main charge that ignites the smokeless load and establishes the initial chamber pressure needed to get the smokeless powder into its fast burn mode.
 
Magnum primers have nothing whatever to do with the cartridge name. They're only about the powder used.
"...H110/W296, yes..." Not necessarily. Hodgdon's site shows primers matching the cartridge name for unknown reasons. Neither H110/W296 when used in say, .30 Carbine, have magnum primers listed.
Your copper plated Xtreme's use cast bullet data and your CCI 500 primers will be fine with either Bullseye or Unique. Neither of which ever need magnum primers. Partial to Bullseye myself. Only because I use it for nearly everything.
 
Magnum primers have nothing whatever to do with the cartridge name.
Click to expand...

Except in the Lyman manual, which I stated as fact rather than opinion. The format of the book expresses primer requirements by cartridge specs, not by powder. For example, 357 Magnum specifies CCI 550 for primers used.
 
I use exactly what the manufacturers recipe calls for. If I'm loading from hodgdon data, that usually means remington 2 1/2. From hornady data sometimes that means CCI 350(I think). The point is I only shoot a few thousand 44 RM rounds / year. I use what the call for. For automatics where I shoot a lot more, I'll rework my loads and substituted. It usually comes out to be no different. In magnum I'm more careful - no deviation. But that's just me.
 
I use standard primers for everything too. Except for the powders that need or like it. For example, 4227 loads like the magnum primer. H110/296 needs the magnum primer. I have tested a few of my favorite loads with both and satisfied myself that I can substitute if I need to. Also found some powders just like one or the other by target results and chronograph stats. All a game we play to find accurate loads :) .
 
So far I have not found a need to second guess load sources about using standard primers with IMR 4227. I use it in 45 Colt, 44 Magnum, and 41 Magnum, depending on bullets and intended purpose. I have found some benefit in using magnum primers to get a more complete burn with HS-6. I will watch for signs of IMR 4227 being a problem with standard primers.
 
I use magnum primers to ignite my H110/296 loads in 300blkout. Especially in winter conditions i found EXTREME velocity deviations during load development when using std primers

Switched to mag primers and the SD dropped into normal ranges. That powder is just HARD to get full ignition when its cold (+\-10degrees)
 
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