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Old August 23, 2012, 01:06 PM   #1
hulley
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Please explain primers.

From what I understand there are only two primer sizes, small and large. However there is pistol, magnum and rifle types. I'm only loading pistols right now but I'm about to start loading 38/357 and 30-30 plus 327fed-mag in the future.

I've been told that magnum primers are not that necesary for 38/357 but are for the 327fed-mag and obviously I'd get large rifle for the 30-30.

My main question is, if the sizes are the same (small,large) what is the difference in ignition? Sorry if this seems like a dumb question

Thanks,
Steve
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Old August 23, 2012, 01:38 PM   #2
SL1
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Small rifle primers are the same physical size (diameter and thickness) as small pistol primers.

Large rifle primers are the same diameter as large pistol primers, but thicker.

That means that putting a large rifle primer in a case designed for a large pistol primer will make the primer stand out beyond the case head (i.e., a "high primer"). A high primer is dangerous, because it can be set-off by things besides the firing pin. For example, if there is a cartridge with a high primer in a revolver, and a heavy-recoiling cartridge is fired in another chamber, the high primer can be banged against the recoil shield behind the cylinder hard enough to set-off the cartridge while the chamber it is in is not aligned with the barrel. That can mean that the bullet cannot get out of the chamber, and the cylinder will explode.

Also, using pistol primers in rifle cartridges that are fired at higher pressures can result in the pistol primer being pushed back against the firing pin hole hard enough for the primer to "pierce" and let hot gases flow back into the gun's firing mechanism, and potentially into your face. That can damage the gun and injure you.

Going the other way, using a rifle primer in a pistol cartridge might (or might not) result in the gun not being able to fire the cartridge because the gun's spring might not be powerful enough to hit the stronger rifle primer cup hard enough to set it off.

So, use the proper primers for the cartridge you aare loading, no matter what else fits.

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Old August 23, 2012, 01:44 PM   #3
hulley
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I understand the difference in rifle vs. pistol now, but what about pistol vs. magnum? I came across two different people at different times and they both use small pistol in their 38/357 loads. If I need to get magnum primers thats fine, but it would be great if I could do both with one.
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Old August 23, 2012, 02:06 PM   #4
357gp
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Certain powders are more difficult to ignite & require magnum primers. H110 & Win296 (same powder) require magnum primers. There are many others, but those are commonly used in the .357
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Old August 23, 2012, 02:19 PM   #5
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Try and look at primers without the "magnum" name. For this discussion, let's call 'em HOT and regular. The reason I say this is that people confuse "magnum" with their cartridge.

A .357 "Magnum" doesn't necessarily require a "magnum" primer. It's the load data and more specifically the powder that demands the HOT primer. A HOT primer has a thicker cup and burns a bit longer with more intensity. The purpose of the HOT primer is to reliably ignite certain powders that are notoriously hard to evenly and properly start. Perhaps the finest example of such a powder is H-110 or W296. These powders always require a HOT primer.

I make a slew of .357 Magnum loads and I haven't once yet EVER used a HOT or magnum primer at my bench. Quite literally, I've experiment with easily more than a dozen and a half different .357 Magnum loads in many bullets weights and with a lot of different powders. Still have never bought nor ever primed any case with a magnum primer. Never say never, but I don't intend to.

Many folks have stated that the evidence suggests that a small rifle primer and a small pistol magnum primer are the same primer. Of this I cannot be sure, but IIRC, someone in the industry stated that this was fact with regards to his company's primers.

One thing that jumps out to me from your post is that you intend to load .327 Federal Magnum in the future. For this round, do absolutely use a small rifle primer in your loads. The original factory ammo all made by Federal/Speer (ATK) is and has always been loaded with small rifle primers. It's my suggestion that no matter WHAT the load data says from any source, work your .327 Federal loads with small rifle primers.

Why that matters: rifle primers have a thicker primer cup and that cup contains the pressure in the round as it attempts to go anywhere to escape. Using small pistol primers in high-pressure loads can lead to pierced and leaking primers. Firearm and personal damage can result. .327 Federal runs a maximum pressure that's significantly higher than most typical handgun rounds that we are familiar with.

Last primer tip for this post: all primers are NOT created equal. Primers from different manufacturers will absolutely act differently in your loads. Where this matters to you is that if you are working at starting level loads, try whatever you like -- even "magnum" primers. But when you start advancing a load and taking it toward the redline -- NEVER just start working with a new primer. Re-work the load from a safe point. If you take a load you've developed and it's a HOT one and you run out of XXX brand primers and simply buy a box of YYY primers and keep loading those HOT loads, that's where you set yourself for failure.
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Old August 23, 2012, 02:21 PM   #6
Old 454
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also there are pistol cartridges that require small rifle primers.... 454 casull is one
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Old August 23, 2012, 02:31 PM   #7
Sevens
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The trend for the big bore rounds (.460 and .500 Smith & Wesson Magnum) is to use a Large Rifle primer.
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Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.
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Old August 23, 2012, 03:06 PM   #8
hulley
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Thanks Sevens, that really cleared things up. BTW I've especially liked reading your posts on the 327FM, thats much of what is making my decision kinda difficult! I say kinda because I plan on owning both a .357 and .327!
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Old August 23, 2012, 03:23 PM   #9
Mal H
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Quote:
Try and look at primers without the "magnum" name. For this discussion, let's call 'em HOT and regular. The reason I say this is that people confuse "magnum" with their cartridge. .... It's the load data and more specifically the powder that demands the HOT primer.
Those few sentences are about the best explanation ever given on these pages when trying to explain magnum primers. So many newcomers to the reloading scene tend to think that if their cartridge is labeled "Magnum" then so should their primer, and vice versa.
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Old August 23, 2012, 09:53 PM   #10
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I will add my +1 for a very good explanation Sevens.
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Old August 24, 2012, 12:51 PM   #11
Sevens
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Thanks guys.
Quote:
So many newcomers to the reloading scene tend to think that if their cartridge is labeled "Magnum" then so should their primer, and vice versa.
The word "magnum" is a marketing tool and it really has been since it debuted with the .357 Magnum. Well, debuted in our corner of the world. Before the first Registered Magnums, "magnum" was a large bottle of champagne, and little else as far as I know.

The term ends up being one of those annoyances that are not held to a standard. Perhaps the finest example is the .32 H&R Magnum which, by any rational line of thinking should have most definitely been named the .32 H&R Special and nothing more. Look at the muzzle velocities and SAAMI max pressure of the cartridge for all the evidence you might need.

When the first "magnum" primers were debuted (I have no idea), it would have been quite nice of them if they'd found a different name for them. I consider this one of those annoyances that complicate things for those new to this hobby -- not at all unlike the Hodgdon "Clays" series of powders where we have "Clays", "International Clays" and "Universal Clays." More and more we see them being simply called "International" and "Universal" but jeez, something this important should never be made easily confused.

My next annoyance which I will not address: Boutique ammunition producers that label and market "+P" products in any chambering that isn't .38 Special, 9mm and .45 Auto, with an exception for .38 Super. (another annoyance)

I need to get some coffee.
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Old August 24, 2012, 01:10 PM   #12
hulley
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Do powders state what type of primer is recommended or is there something else to look for. I'm currently using W231 but I bought Unique and 2400 for the 38/357 loads. Ordering bullits tonight, probably from Missouri.
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Old August 24, 2012, 01:54 PM   #13
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Usually the powder containers themselves don't specify what primer to use.

However, the load data provided by the powder manufacturers and the bullet manufacturers almost always provides the primer brand and type used to create the loads that were pressure tested. It is best to try to duplicate the primer/powder combination of whatever data you are using, including the BRAND of primer.

There are occassionally bits of data published to show the potential problems with switching primer brands. In the most recent edition of Handloader Magazine, some data from Western Powders was published showing the following with a "Ruger only" .45 Colt load using a 310 grain cast lead bullet and 21.0 grains of Enforcer powder:

Code:
Primer      Velocity     Pressure
CCI 350    1,352 fps    35,950 psi
Rem 2½     1,238 fps    23,990 psi
Win LP     1,239 fps    22,490 psi
Fed 155    1,278 fps    27,870 psi
So, substituting a CCI 350 primer in data developed with a Win LP primer could increase this particular load's pressure by more than 13,000 psi. That is definitely not something that you would want to have happen if you were shooting one of the Rugers built on their mid-sized "Flat top" frame instead of one built on their large frame. In this particular load, the 100 fps increase in velocity should be a tip-off that something is not as expected. But, such velocity increases are not always so apparent when there are substantial pressure increases. And, not everybody is using a chronograph so that they would know that there was a velocity increase.

So, start with primers that are used to create whatever data you are using, rather than experiment or take some store clerk's recommendation.

SL1
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Old August 24, 2012, 02:19 PM   #14
hulley
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Thanks SL1, I'll definitly take that info and use it well. I dont want to ruin a gun or me!
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Old August 24, 2012, 02:27 PM   #15
Mal H
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Quote:
I consider this one of those annoyances that complicate things for those new to this hobby -- not at all unlike the Hodgdon "Clays" series of powders where we have "Clays", "International Clays" and "Universal Clays." More and more we see them being simply called "International" and "Universal" but jeez, something this important should never be made easily confused.
In the "things the marketing department should never be in charge of" category, that one has been on my really-annoying list for a long time:

http://thefiringline.com/forums/show...307#post180307

http://thefiringline.com/forums/show...799#post604799
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