Primers for 327 Federal Magnum

R

Real Gun

New member
Speer recommends Small Rifle primers when loading the upper range of 327 out of concern for primer flowback. It seems they are alone in that recommendation for this caliber. I was advised at one point that rifle primers would stand proud and bind up a cylinder, but the WSR primers I have tried are flush with no feel of being forced. The CCI Small Rifle Magnums same thing. I intend to follow the Speer advice to use rifle primers with 327 Federal Magnum, which by the way, as a newer cartridge, is a downloadable supplement to their current edition of the load book.

I have loaded samples of Small Pistol, Small Pistol Magnum, Small Rifle, and Small Rifle Magnum primers, although Speer recommends NOT using magnum rifle primers, and I don't really intend to use that type except maybe for lack of any other supply. All of these are with 327 cases, Penn LRNFP 95 gr, and 12.0 gr AA#9. Test gun will be a 4" SP101.
 
.327 Federal uses small rifle primers in full power loads. It's necessary at the MAP of the cartridge.
Factory ammo from ATK (Speer, Federal, American Eagle, etc.) uses small rifle primers. ...As do I.

Small rifle and small pistol primers share the same external dimensions.
Where a rifle primer will 'stand proud' in a pistol primer pocket, is in the world of large primers. Large rifle primers are nominally 0.008" longer than large pistol primers; and the large rifle primer pockets are correspondingly deeper.


With some 'hot' loads, you can get away with small pistol magnum primers in .327 Federal. But with max loads, you really should be running small rifle primers. Small pistol primers, even the magnums, really aren't mean to handle the pressure that .327 Federal can produce (45k psi).

The reason you shouldn't use small rifle magnum primers, is that the primer is more energetic and starts the bullet deeper into the forcing cone and barrel. This causes reduced starting pressure, which makes it harder for the powder to burn properly (deflagrate, actually). Under the right circumstances, this can result in a flame-out ('fizzle') of the powder, because pressure is lost when the bullet clears the forcing cone gap.
And even if it doesn't 'fizzle', you can encounter erratic performance.

Contrary to popular advice, I tried it. Performance was... ridiculous and unpredictable, to say the least.


Some of the things I won't ever try, or won't ever try again, in .327 Federal:
1. Blue Dot.
2. True Blue.
3. Small rifle magnum primers.
 
Small pistol, Small Pistol Magnum, Small Rifle, and Small Rifle Magnum primers are physically all the same size. Large Pistol, Magnum and Standard are shorter than Large Rifle primers (about .010"). Large Rifle primers, being taller will "stand proud" of the pistol case head...
 
There's not much "official" data on the 327 Fed Mag, but the Hodgdon website uses the Federal 200 (small pistol magnum) for its 327 Fed Mag loads. That's what I've been using, and although I'm an admittedly novice user of the 327, I haven't had any ignition problems. My understanding is that small pistol magnum primers and standard small rifle primers are, at least for CCI, the same animal.
 
Ballisticians at ATK have told me specifically via e-mail (and told others also) that all the ATK brands that produce factory ammo for the .327 Federal use small rifle primers specifically, from day one to the present, and that is the final word. 45k PSI Max demands it. None of the other big ammo makers (Winchester, Hornady, R-P, Fiocchi, Magtech, Prvi Partizan, S&B, PMC...) have ever made .327 Federal. The only other sources for "factory" .327 Federal ammo are from boutique ammo makers such as Buffalo Bore and etc.

I also use small rifle primers (CCI-400) in my .327 Federal with the very rare exception of very light bullet, lower velocity loads such as plinking with the 71gr FMJ bullet. Those loads are so light that they often barely drop steel plates at 10 yards... I don't make a lot of that these days... but maybe it's time to roll a batch.

When I use the 85 or 100gr XTP, and I make ammo with Longshot, 2400, AA#7, AA#9, Power Pro-300MP... I am using CCI-400 Small Rifle primers.
 
So why introduce "small rifle" primers to pistol loads, when "small pistol magnum" is the same thing? Just because Winchester makes no distinction for magnum shouldn't cause the confusion.The cartridge is a small pistol magnum, so it certainly would be easier to make a direct association with a primer.
 
If a gun needs small rifle primers in a 327F, it must have a terrible firing pin to firing pin hole fit.
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Here is an example where I needed CCI450 magnum small rifle primer for the thicker cup to deal with terrible firing pin to hole fit.

In 6mmBR that primer is needed up around 80kpsi, even with a good fit. Some bush the pin to go even higher.
 
If a gun needs small rifle primers in a 327F, it must have a terrible firing pin to firing pin hole fit.
Click to expand...

Reason given was to prevent "primer flowback".

ref:
Speer supplement for 327 Federal Magnum
 
Is that the same Speer load book that says the 30-30 case is weak?
I think that is Speer 12 1994.

I give it 5 Pinocchios.
 
I am trying to be helpful, but succinct.

I used to get calls when engineers were stuck. 90% of the time I could get them to solve their own problem if they would just let go of the way they looked at a problem. I still got paid.

After I see that over and over I have to ask, "What is it that I am hanging onto that is holding me back?"

But we can't answer that because what holds us back is what we believe, and WE BELIEVE IT.
 
Speer's supplement for 327 Federal Magnum bears a copyright of 2012. My Speer book has a copyright of 2007.

As far as a 20 year old factoid re 30-30, one of the problems with printed sources of any kind is the errata. PDFs are a problem too, if not replaced with edited versions. Of course, wikis are inherently suspect too, as are online forums. One has to either pick their own authorities or use whatever qualifications they might have of their own. I tend to treat reloading manuals with biblical reverence. At the same time I use my nonsense meter for all sources. I am not sure what else should be expected.
 
Everything I put in wikipedia eventually gets edited out.
I give up.
The only thing one can do is message to a wiki big shot and have them enter it in THEIR own words.

The usenet forum rec.guns has been moderated by a computer science professor since the early 90s. I saw him fight for years to get something into the Smith and Wesson boycott wiki.

I don't have the talent nor the energy to change wikipedia.
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There are two disadvantages to going to a small pistol magnum primer when not needed:
1) More pressure for a given velocity
2) Harder to set off

The advantage looks like:
1) Less primer flow back

None of these 3 issues are worth worrying about, unless you have a super hot load, super wimpy hammer spring, or super bad firing pin fit.
 
There are two disadvantages to going to a small pistol magnum primer when not needed:
1) More pressure for a given velocity
2) Harder to set off

The advantage looks like:
1) Less primer flow back

None of these 3 issues are worth worrying about, unless you have a super hot load, super wimpy hammer spring, or super bad firing pin fit.
Click to expand...

327 Federal Magnum probably qualifies as a "super hot load".

Hammer spring is a real issue with the Ruger SP101, one of the premier 327 Fed Mag guns. If I try to make the action too elegant in feel, I get light strikes. I am currently at 12 lbs using the Wolf spring kit, but the gun came with what I believe was 14 pounds. A cursory check of a batch of fired brass shows primer strikes often not dead center but all appear to be decisive strikes and they certainly fired...not sure of which of four guns fired them.
 
Brian Pearce addressed this issue in Handloader #294, at pp. 30-34. He concludes that "ordinary" CCI #500s are sufficient for all loads.

By the way, this article has the most extensive load data of any I have seen so far.
 
Real Gun
327 Federal Magnum probably qualifies as a "super hot load".
Click to expand...

It would for guns with high force extractors, but for revolvers with multiple chambers at once doing fingertip extraction with no leverage, the pressure is probably going to be less than 45,000 psi Quickload.

I think all published loads for 357F will be friendly to revolvers.

If I build a rifle in 357F, i would expect the standard pistol primers to give up the ghost at 140,000 psi QL, and CCI450 to go to 220kpis QL, if 38 special is any example.
 
Remember though, You dont need small rifle primers in all 327 mag loading.
They are only needed if high pressure loading's.
If your loading fun gun cast bullet loads. Regular small pistol primers are just fine.

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