Rifle loads and Magnum Primers

[JohndeFresno]

There is an interesting article by Layne Simpson, in his "All That Brass" Department of the latest RifleShooter Magazine (May/June 2012, Pgs. 20, 23).

In his article, "A Primer Primer," Mr. Simpson delves into a lot of interesting particulars, but among them are these nuggets:
1) He switches to a magnum primer if the powder's burn rate is slower than IMR-4350;
2) "Especially true if the powder charge exceeds 55.0 grains in weight;"
3) Uses magnum primers for any ball or spherical powder with charges exceeding 35.0 grains;
4) And, predictably, uses a magnum primer when shooting temperatures drop below freezing.

EDITED: He outlines an experience that emphasized the danger of using small pistol primers as a substitute for small rifle magnum igniters.

And he mentions the little known CCI 41/5.56mm and 34/7.62 primers that were designed to prevent slam-fires in semi-auto and full auto rifles.

I thought that the two page article was concise and quite relevant for rifle shooters and hunters.

[AJMD429]

I need to re-up my hard-copy subscription to Rifle and Reloader - I got them 'online' but never wound up reading them like I did the paper versions...

[JohndeFresno]

Doc, just in case you or somebody missed it:
There is the online subscription trio of Handloader, Rifle Magazine, and Successful Hunter. This is another Petersen's Publishers magazine - RifleShooter.

[Mike D.]

I use them with heavy loads of smokeless in large volume cases like .40-82 and .45-90.

[earlmck]

He outlines an experience that emphasized the danger of using small pistol magnum primers as a substitute for small rifle magnum igniters.

Yeah, the small pistol magnum is equivalent to the regular small rifle, not the small rifle magnum. (for CCI, anyway)

[JohndeFresno]

I use them with heavy loads of smokeless in large volume cases like .40-82 and .45-90.

How 'bout your .45-70 loads?

[JohndeFresno]

He outlines an experience that emphasized the danger of using small pistol magnum primers as a substitute for small rifle magnum igniters.

Yeah, the small pistol magnum is equivalent to the regular small rifle, not the small rifle magnum. (for CCI, anyway)

His incident involved a Marlin 1894 in .357 Magnum. Using the pistol magnum primer, it drove the bullet "about an inch into the barrel, but it was not hot enough to ignite the N110 powder." The powder was found compacted "into a pellet" at the base of the bullet.

This article definitely got my attention.

[preventec47]

[quote="JohndeFresno"][quote="earlmck"][quote="JohndeFresno"]He outlines an experience that emphasized the danger of using small pistol magnum primers as a substitute for small rifle magnum igniters.[/quote] Yeah, the small pistol magnum is equivalent to the regular small rifle, not the small rifle magnum. (for CCI, anyway)[/quote]
His incident involved a Marlin 1894 in .357 Magnum. Using the pistol magnum primer, it drove the bullet "about an inch into the barrel, but it was not hot enough to ignite the N110 powder." The powder was found compacted "into a pellet" at the base of the bullet. [/quote]

I dont get it. The 357 magnum is a pistol caliber right ?
So he is suggesting to use rifle primers in pistol calibers ?
What is the difference. Is the point that of the N110 powder
being a rifle powder and not used in pistols ? ? ?

I was going to say what if he shot that load in a revolver?
Is he supposed to use a rifle primer in the revolver ? ? ?

[Griff]

I've tried them in my .40-90SBN. I couldn't say that it was any improvement... but I couldn't say it hurt either... only used BP tho'.

[JohndeFresno]

...I dont get it. The 357 magnum is a pistol caliber right ?
So he is suggesting to use rifle primers in pistol calibers ?...

Preventec,

APOLOGIES. My back is out, I'm dealing with something that involves a sore throat, and after this post I'll stay off for a while. I tried to constrain myself from quoting too much of the article for fear of violating copyright laws (and the author's fair royalties).

In the process, I typed in the word "magnum" erroneously - a big error.

1) Author did not have a small pistol magnum primer; so he used a standard small pistol primer for the .357 levergun load and N110.
2) He used a standard WSP - Winchester Small Pistol primer.
3) Federal 205 Small Rifle primers stopped the misfires with that powder.
He says, "Small Pistol primers should never be used in rifle cartridges, but since the cups of Small Rifle primers are thicker and often harder, they are sometimes used in handgun cartridges" loaded to high pressures.

I am glad that you caught the error. I'm going to do some reading and rest until whatever is ailing me goes away. Gotta be careful here.

[Mike D.]

I use them with heavy loads of smokeless in large volume cases like .40-82 and .45-90.

How 'bout your .45-70 loads?

Yes, especially with lighter the bullets I favor. Also the .38-56, but not .30-30, .30-06 and the like.

[damienph]

I use them with heavy loads of smokeless in large volume cases like .40-82 and .45-90.

How 'bout your .45-70 loads?

Yes, especially with lighter the bullets I favor. Also the .38-56, but not .30-30, .30-06 and the like.

Mike D, I am curious about your preference for magnum primers when shooting lighter bullets (in 45-70). What difference do you think it makes? I've always just used regular large rifle regardless of bullet weight. I've been handloading for a long time (30+ years) but my experience is limited with the 45-70.

[earlmck]

1) Author did not have a small pistol magnum primer; so he used a standard small pistol primer for the .357 levergun load and N110.

I also have had the standard small pistol primer fail to ignite ball (H110) powder in a 357 magnum. In my case this was in the Ruger SP101. Happened once and I dug the wad of unburned powder out, pounded out the bullet that had gone in a couple inches, scratched head and figured it was a total unexplained fluke. Happened once again some months later. This time I finally wised up and switched to magnum primers for the ball powders (yes, the loading books all call for the magnum primer but I am an old know-it-all and didn't believe 'em). Have not had another instance of failure to ignite since the switch. And the cold chills that run up my spine thinking of the times I have blasted off 6 rounds double action fast as I could pull 'em off and what would have happened... well, maybe those chills helped me to be less of a know-it-all than I used to be.

[Old Savage]

Don't have time to go into this now but I never use magnum primers - shoot no magnums and get top velocities in the standards and what seems like top accuracy from a hunting standpoint. I use WLRs. I think the need for magnum primers starts over where Simpson thinks they do. But coming down from things like the Shooting Times Westerner may distort his frame of reference. Loads available upon request. And by the way - nobody named TERRY has ever given me one bit of useful advice - but I didn't ask - in my reloading and no animals were injured in the typing of this response.

[JohndeFresno]

OS, I was going to say something clever in response, but I can't spell "curmudgeon"...

[El Chivo]

I haven't used magnums in rifle cartridges, but I have used both in .357 and I got fewer unburnt kernels with the magnum. I also got better accuracy.

My understanding is magnums increase pressure by 10%. I think of it as just another variable. I would consider using them but not for full house loads. I have been wondering if they would help with unburnt kernels (and accuracy) with SR 4759 in reduced rifle loads.

[preventec47]

In the December issue of Handloading Magazine, Several
ballisticians were debating the wisdom of use of magnum primers with several different powders and in some instances
they argued that the magnum primers increased the peak
pressures without significant increases in velocity and in
situations where magnums were not needed, all they
did was eat into our safety margins. Conversely, they
argued that an increase in powder that would achieve
the same increase in peak bore pressures would in fact
increase the velocity. Now I think they were mostly
talking about pistols but cannot remember well. I do
recall that one of the biggest mistakes were for people
that were shooting magnum calibers thinking that they
always needed magnum primers as that was not true.
I must admit, I do not know when magnum primers
are needed other than when it is very very cold.
I suppose there are some powders that are very hard
to ignite but I dont know what those are but I suspect they likely are far more prevalent in the higher power slower burning rifle calibers than in pistols.

[Old Shatterhand]

In the loading data, Norma switched from standard primers to magnum primers for most rifle catridges some years ago. However, at the same time they reduced the loads with 2-4 grains, depending on the volume of the case. They claim that the magnum primers increase peak pressure, but also that they give better ignition under very cold circumstances.

However, I go on using my old loads with standard primers. They work well and I don't want the increased peak pressure. "Don't fiddle with that which works!"

Pete

[Mike D.]

I have a lot of Winchester "Large Rifle and Magnum" primers that I pretty much use exclusively these days. CCIs have been sometimes reluctant to ignite in those pesky weak spring Miroku rifles. Original Winchesters never fail to ignite anything.

[Old Time Hunter]

Don't have time to go into this now but I never use magnum primers - shoot no magnums and get top velocities in the standards and what seems like top accuracy from a hunting standpoint. I use WLRs. I think the need for magnum primers starts over where Simpson thinks they do. But coming down from things like the Shooting Times Westerner may distort his frame of reference. Loads available upon request.

Totally agree, never have noticed any measurable difference.

[1894c]

thank you for the post and the great discussion...got me thinking... :)

[FWiedner]

3) Uses magnum primers for any ball or spherical powder with charges exceeding 35.0 grains;

I keep reading that this approach works, but it's not produced good results for me, specifically with Win 748.

[COSteve]

I've switched to magnum primers for all my ball powder loads except Win 748 and 760 where I use Winchester LR primers exclusively after talking with the Winchester rep. However, all my other loads, especially H110 and Power Pistol loads get a magnum primer. It's not that I have significant issues so much with incomplete ignition (I have had a few) but rather my chrono work has shown repeatedly that I get much more consistent velocities. The chrono shows lower ES and SD numbers when using the magnum primers over the standard ones every time.

In fact, I consistently get the lowest ES and SDs when using SRM primers (yep, small rifle magnum) in my 357mag and 30 Carbine loads even though the books call for plain SP primers. I get consistently higher velocities and much more consistent (lower) ES and SDs when using Power Pistol and magnum primers in my 40s&w, 45acp, and 10mm handgun loads too. All one need do is make sure you work up to them and you're fine.

I've noted that when swapping SRM primers for SP primers, I settle on loads that have about ½ grain less powder for the same velocities in my pistol loads and about ⅓ grain less in my rifle loads when using magnum primers. Some old timer reloaders who helped me learn gave me that tip and said that they followed the ½ grain lower 'rule' when using magnum over regular primers in their pistol loads and that's turned out to be right.

Finally, I talked some years back with a wonderful woman tech at CCI asking about the difference between their SPM and SR primers spec wise. She looked them up and told me that they are the same diameter, height, use the same thickness primer cup, use the same charge formula and have the same amount of charge in them. I asked her if that didn't mean that CCI's SPM and SR prmers weren't the same items and she just chuckled. She did mention that while SP and SR primers were the same size, LP and LR primers were different with the LR primers being a bit taller than the LP so you couldn't swap one for another of those.

[JohndeFresno]

Yeah, the small pistol magnum is equivalent to the regular small rifle, not the small rifle magnum. (for CCI, anyway)

I've switched to magnum primers for all my ball powder loads except Win 748 and 760 where I use Winchester LR primers exclusively after talking with the Winchester rep. However, all my other loads, especially H110 and Power Pistol loads get a magnum primer. It's not that I have significant issues so much with incomplete ignition (I have had a few) but rather my chrono work has shown repeatedly that I get much more consistent velocities. The chrono shows lower ES and SD numbers when using the magnum primers over the standard ones every time.

In fact, I consistently get the lowest ES and SDs when using SRM primers (yep, small rifle magnum) in my 357mag and 30 Carbine loads even though the books call for plain SP primers. I get consistently higher velocities and much more consistent (lower) ES and SDs when using Power Pistol and magnum primers in my 40s&w, 45acp, and 10mm handgun loads too. All one need do is make sure you work up to them and you're fine.

I've noted that when swapping SRM primers for SP primers, I settle on loads that have about ½ grain less powder for the same velocities in my pistol loads and about ⅓ grain less in my rifle loads when using magnum primers. Some old timer reloaders who helped me learn gave me that tip and said that they followed the ½ grain lower 'rule' when using magnum over regular primers in their pistol loads and that's turned out to be right.

Finally, I talked some years back with a wonderful woman tech at CCI asking about the difference between their SPM and SR primers spec wise. She looked them up and told me that they are the same diameter, height, use the same thickness primer cup, use the same charge formula and have the same amount of charge in them. I asked her if that didn't mean that CCI's SPM and SR prmers weren't the same items and she just chuckled. She did mention that while SP and SR primers were the same size, LP and LR primers were different with the LR primers being a bit taller than the LP so you couldn't swap one for another of those.

Aha!
Thanks a lot, gents. And thank you for everybody's input. This whole thread has been an eye-opener for me. Y'all might want to pick up an issue of the current RifleShooter to have the complete article on hand.

[Old Savage]

I have found both excellent accuracy and velocity in the 7-08 using H380 with the Win WLR primers.

[pokey]

Original Winchesters never fail to ignite anything.

i've noticed that, myself.

[earlmck]

Mike D. wrote:
Original Winchesters never fail to ignite anything.


i've noticed that, myself.

I beg to differ, fellows. I mentioned in an earlier post that I'd had two "failures to ignite" in the .357 with ball powder (H110) using regular small pistol primers. I went to my notes (yes, I've got reload notes going back that far) and the primers that did the dirty were Winchester. That being said, I use standard primers for everything but slow ball powders in large cases for any cartridge that takes the Large size. For the small primer size, however, I will forevermore use the mag pistol or regular rifle primer with the slow ball powders. Two "failures to ignite" were two too many for this kid.