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View Full Version : Rifle VS Pistol VS Magnum Primers


chasep255
April 11, 2011, 05:51 PM
It seems to me that primers on;y come in two sizes Small and Large. So what is the difference between a small rifle primer and a small handgun primer? They have the same dimensions. What would happen if I made some .40 S&W using small rifle primers?

PA-Joe
April 11, 2011, 06:52 PM
Wrong, the rifles produce a hotter fire and may discharge the pistol bullet before the powder goes off. They are also not the same height. The metals are also harder so a pistol primer in a rifle may get pierced and a rifle in a pistol may not fire.

Ideal Tool
April 11, 2011, 07:11 PM
Hello, chasep255. You would probably get mis-fires using small rifle in a pistol. You can have primer piercings from using pistol in rifle cases..although some BPCR shooters use large pistol primers & claim better accuracy. S.P. & S.R. have same height..L.P. are about .010" shorter than L.R. primers.
It looks to me that you could do a bit of reading up on handloading basics before even attempting this facinating...but sometimes unforgiving hobby.

454PB
April 11, 2011, 09:02 PM
The external dimensions of small pistol and small rifle are the same. Small rifle primers have a thicker cup and a higher brisance priming mixture, and small rifle magnum primers have a still thicker cup. If you use small rifle primers in a handgun, it may work OK if the firing pin strikes hard enough. The extra power of the priming mixture may be a problem, depending on the powder and amount used.

Large rifle primers are the same diameter as large pistol primers, but are taller. The thicker cup and hotter priming mixtures also apply. If you seat a large rifle primer in a pistol case, the primer will protrude and can actually prevent the cylinder from rotating in a revolver. In the case of an auto loader, the cartridge could slam fire.

Shoney
April 11, 2011, 10:23 PM
The chart at this site is very good. At the bottom are the primer dimensions.

http://www.lasc.us/primerchart.htm

You can substitute a magnum primer for a standard primer by reducing the load and working back up, watching pressure signs closely.

Clark
April 11, 2011, 11:50 PM
PA-Joe
Wrong, the rifles produce a hotter fire and may discharge the pistol bullet before the powder goes off. They are also not the same height. The metals are also harder so a pistol primer in a rifle may get pierced and a rifle in a pistol may not fire.

Large pistol and Large rifle has different heights, but overlap a little, and I can alway seem to get away with it.

Small pistol and rifle are the same height.

So you corrected someone when YOU were wrong.


Depth min max diameter min max
small rifle primer pocket .117 .123 .1730 .1745
small pistol primer pocket .117 .123 .1730 .1745
Large rifle primer pocket .125 .132 .2085 .2100
Large pistol primer pocket .117 .123 .2085 .2100


Height min max Diameter min max
Small rifle primers .115 .125 .1745 .1765
small pistol primers .115 .125 .1745 .1765
large rifle primers .123 .133 .2105 .2130
large pistol primers .115 .125 .2100 .2120"

SAAMI specifications on primers and primer pockets per "Sinclair International's Precision Reloading & Shooting Handbook" 10th edition 1999

FrankenMauser
April 12, 2011, 01:40 AM
Clark, you need to edit your signature to include something to the effect of:
"I blow firearms up for a living. Don't use any of my advice in standard reloading practices."

Using your own numbers shows that using an average height Large Rifle primer (0.1275") in an average depth Large Pistol primer pocket (0.120") will give 0.0075" of exposed primer.

A maximum height Large Rifle primer (0.133") in a minimum depth Large Pistol primer pocket (0.117") will give 0.016" of exposed primer! That's nothing to be casual about.


Otherwise.... 454PB pretty much nailed it.

Clark
April 12, 2011, 02:04 AM
FrankenMauser
Senior Member

Join Date: August 25, 2008
Posts: 2,617
Clark, you need to edit your signature to include something to the effect of:
"I blow firearms up for a living. Don't use any of my advice in standard reloading practices."

Using your own numbers shows that using an average height Large Rifle primer (0.1275") in an average depth Large Pistol primer pocket (0.120") will give 0.0075" of exposed primer.

A maximum height Large Rifle primer (0.133") in a minimum depth Large Pistol primer pocket (0.117") will give 0.016" of exposed primer! That's nothing to be casual about.


Otherwise.... 454PB pretty much nailed it.

I think the OP was about small primers.

chasep255
April 12, 2011, 08:36 AM
I think the OP was about small primers.
That was just my example. This is about all primers. But by now I think I have my answer which is don't mix them so thanks.

LarryFlew
April 12, 2011, 10:27 AM
Gotta love it when the OP finally answers his own question after all of the detail goodies have been presented in so many different ways.:rolleyes:

mikld
April 12, 2011, 11:24 AM
When I started reloading, I just read the box. Then I used a small pistol primer in small pistol primer applications, (as stated in my reloading manual) same with large primers and magnum primers. Now that I have nearly 30 years of reloading under my belt and been reading questions/answers like this for the past 10 years, if I want to I can cheat a little but I know the consequences if I do...

GeauxTide
April 12, 2011, 12:17 PM
There are decades of science and some pretty smart people behind primer development. Use primers for the specified and intended purpose. What would happen if you used diesel in your gas engine or gas in your diesel? What if you used 100-1 oil mix in your 2 cycle engine that calls for 50-1? It might run, but..............

Unclenick
April 12, 2011, 01:01 PM
CaseP225,

I like to recommend this article (http://www.shootingtimes.com/ammunition/ST_mamotaip_200909/index.html) as a primer on primers.

Clark
April 14, 2011, 11:07 AM
Brissance is one of those concepts they did not teach us, like center of percussion or shock simulation with vibration spectrum dwell time.

Usertag
April 14, 2011, 11:12 AM
454PB is your best answer. And i can't remember if he mentioned this. But rifle primer's are a bit harder.

Civil War Life
April 14, 2011, 12:15 PM
Hope this isn't hijacking a thread as this is related. I bought some small pistol primers. I had asked for CCI 500, but got CCI 550s. I am buying a new S&W M&P 9mm and was going to use these to load some ammo. I loaded up 25 rounds using the 550s at the lowest powder charge level. Are these safe to shoot or should I pull the bullets and lower the powder charge? How much lower should I go to use Magnum primers? Can these also be used for 38 special?
Thanks. Terry

Unclenick
April 14, 2011, 04:21 PM
Lowering charge weight to starting loads will tend to cover the difference between standard and magnum primers. There are funny situations where magnum primers can actually lower peak pressure by unseating the bullet ahead of the powder burn, so whatever load you develop, if you change primers to any other brand or kind, go back to the starting load just to be sure.

The military loads all their regular ammo with magnum level primers to be sure of cold weather ignition, so no, there is no inherent concern about using them in the 9mm or even in the .38 Special. Just start your loads at starting levels, and work up watching for pressure signs (http://www.shootersforum.com/showthread.htm?t=58763). Keep in mind that sometimes magnum primers have harder cups, as mentioned, so be sure to get them solidly into the bottom of the primer pocket to give your gun's firing pin the best chance of making them work.

Civil War Life
April 14, 2011, 05:21 PM
Thanks Unclenick

I wasn't really looking forward to pulling them and starting over. I'll try these and see how they work.

Terry

Loader9
April 14, 2011, 08:26 PM
Might wanna search this forum back several years ago. One of the posters asked the same question in regards to small pistol primers and small rifle primers and the difference. He emailed the folks at CCI who answered- Small pistol primers and small rifle primers are one in the same primer- no difference except the label. Those were the only ones he asked about. If you also look at Federal primers #200, the label says small rifle and high velocity pistol primers. Does not say specifically magnum or ball powders.

FrankenMauser
April 15, 2011, 12:56 AM
Might wanna search this forum back several years ago. One of the posters asked the same question in regards to small pistol primers and small rifle primers and the difference. He emailed the folks at CCI who answered- Small pistol primers and small rifle primers are one in the same primer- no difference except the label.

There had to have been some kind of misunderstanding, if that is what the reply boiled down to.

CCI SP primer absolutely cannot handle high pressure.

In addition...
Every article I can find on the net, in reference to cup thickness, puts the CCI SP (#500) cup thickness at 0.017" and the CCI SR (#400) cup thickness at 0.020".

However - The CCI SP Magnum (#550) is said to be exactly the same primer as the CCI SR (#400). And... I was able track down a post referencing this (http://www.sksboards.com/smf/index.php?topic=56422.0) (Post #2. They're not numbered; just scroll down).

Unclenick
April 15, 2011, 10:07 AM
That's possible. But as I mentioned earlier, the primer makers keep changing their formulations. This article (http://www.shootingtimes.com/ammunition/ST_mamotaip_200909/index.html) by a CCI employee is where I got that (same as my earlier link, primer on primers).

Dave R
April 15, 2011, 12:58 PM
Thanks for the linked article, unclenick. I read and it was very educational.

454PB
April 15, 2011, 02:01 PM
However - The CCI SP Magnum (#550) is said to be exactly the same primer as the CCI SR (#400). And... I was able track down a post referencing this (Post #2. They're not numbered; just scroll down).

If this were true, you could substitute CCI 550 primers for CCI 400 primers in the .454 Casull. I don't know if that is a good idea when loading a cartridge than can generate 65K PSI.

FrankenMauser
April 15, 2011, 02:28 PM
If this were true, you could substitute CCI 550 primers for CCI 400 primers in the .454 Casull. I don't know if that is a good idea when loading a cartridge than can generate 65K PSI.

That's right.
And, that's the point of reloading - You'll never know, unless you try it. ;)
I have run both in .327 Federal, with no discernible difference. The only reason I have gone to SR primers as my 'standard' primer, is because they're generally $2-3 cheaper per 1,000 primers.

I just sent an email to CCI, to get an answer directly from them.