Small pistol primers vs. small rifle primers

[chrisp51]

I know there is a difference between small pistol and small rifle primers but what are they? Are they the same in overall dimensions and just different is charge strength? I have lots of small rifle primers but few small pistol. Anyone tried small rifle in small pistol applications.

[Brian Pfleuger]

It depends on the brand, exactly what the differences are.

The external dimensions of SMALL primers should all be the same, not true of large primers.

In the case of CCI, their small pistol magnum and small rifle primers are identical. I don't know about any other brand's specifics.

[jcwit]

There is also supposed to be a difference in the thickness/hardness of the cup of the primer. Thus making it harder for a handgun to set off a rifle primer. In my experience this may be the case but I have yet to have a FTF using SRP in handgun calipers.

[Sevens]

In the same brand, the external dimensions are identical. Across brands, there may be a slight difference, but none that you'd ever notice.

They burn hotter and longer, and they have a thicker cup. It does mean they can be harder for a handgun's hammer hit to set them off, but the design is such that they have the ability to contain more pressure. Some factory handgun ammo is loaded with small rifle primers right from the OEM source (.327 Federal Magnum is an example) simply to guard against leakage or bursting to contain the high pressures. (.327 Federal runs a 45k max psi)

Anyone tried small rifle in small pistol applications.

Many folks use them exclusively, some of them ran out of small pistol during that last component squeeze in 2009 and some of those guys never went back to using small pistol.

[B.L.E.]

Some folks claim that small pistol primers work better in a .22 Hornet but my best groups were shot using CCI small rifle primers.

[BumbleBug]

I have a friend with a Uberdi .38-55 high-wall that was having problems with misfires using CCI. Hammer fall seemed weak to me. He always shoots lead & at cowboy velocity levels so I suggested he use a Lg pistol primer. That worked just fine. Later he switched to (IIRC) Fed Lg rifle primer & that cured the problem too.

[swcc22]

I wouldn't recommend using a small pistol mag primer in a rifle the strike of the pin could poke a hole in the primer do to its softer cap. I have seen it happen but hey that's just my 2 pennies.

[BumbleBug]

Piercing a primer is never a good thing! But in my friend's case it was not likely. My real advice was to get the gun fixed. A weak hammer fall does nothing for the lock time either & effects accuracy. It would be interesting for someone to do a study of different brand primers & their sensitivity & wall thickness. I know this has already been done in regards to brisance & some reg's are mag's & vice versa. In practicality, I'm sure we'd find that one man's rifle primer is another man's pistol primer & vice-versa too!

JIMHO...

[243winxb]

Same size, cup thickness different. These not made for high pressure loadings over 40,000 psi.


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[Clark]

The small rifle magnum primers have the thickest cup.
The small pistol standard primers have the thinnest cup.
Everything in between is in between.

I have a cheap Spanish 25acp that will pierce the small pistol standard primer with hot loads [due to a very bad firing pin to firing pin hole fit] but can not set off a small pistol magnum primer.

[greentick]

I was just thinking about looking for that chart, having seen it posted before. Thanks Clark!

[B.L.E.]

I just miked a 209 shotshell primer and I measure .240, not .209 inches.

Anyone remember when you had to buy #57 primers to reload Remington shotgun shells? They were smaller in diameter than the 209 primers that everyone else used in shotshells.
I have also heard that you could reload 209 primers by punching out the old primer from the battery cup and putting in a new large pistol primer. Probably more trouble than it's worth to save that penny of cost difference if it's indeed true.

[the led farmer]

Originally Posted by chrisp51

...Anyone tried small rifle in small pistol applications.

I have used srp in lieu of spp and exclusively since i went through my first 1k spp. I have not had a single problem.

although i suspect this is more internet myth than reality I loaded one in a resized brass (no powder no bullet) and made sure my pistol would fire it and the rest was gravy.

work up your load and you'll be fine

[steelman762]

Yes I have used small rifle in small pistol. I have only done it with 45acp. I used WSR primers. I chronographed the speed. With the same load 5.5gr Unique and 230gr LRN bullet the average speed changed 100fps. This was the only differance I could detect.

[sea2weed]

Thanks for posting the SAAMI specs! Like many my small pistol supply is just about out so I was debating trying small rifle. Primed a couple of 9mm this morning with CCI small rifle, even though I was single staging with my Rockchucker I couldn't get the primer height below flush?? switched back to CCI small pistol and everything was good with about .003 below. Once fired Federal cases which had been deprimed and tumbled, pockets nice and clean. I could easily apply more seating pressure but my calibrated priming hand was telling me that should have been plenty? I understand CCI primers have a reputation of being some of the hardest, I have some Win and Fed SR's I could try. Anyone have any experience between the different brands when doing this?

[Sevens]

I haven't loaded Federal small pistol in at least a decade...
In your position, here's how I would handle this problem.

I'd take a rag or towel and drape it fully over the press and then I'd keep adding pressure on that press handle until I found either:
1) end of range with no more push possible
2) DETONATION, which will be loud & scary but no major risk if you've got things covered.

Wear safety glasses -- which you should do 100% of the time you are priming cases ANYWAY.

[sea2weed]

Thanks For the response Sevens, I think I'll just leave well enough alone and keep doing what I've done for the last 30+ years. It's not like I don't have plenty of other guns to shoot up the large rifle, large pistol and small rifle primers I do have lots of

[swcc22]

Hey sea where u live? I have some small pistol I might be willing to trade for

[Unclenick]

Originally Posted by Clark

The small rifle magnum primers have the thickest cup.
The small pistol standard primers have the thinnest cup.
Everything in between is in between.

Interesting. This James Calhoun article disagrees, putting large rifle as the thickest. At the same time, he makes them so thick I believe his numbers are actually the difference between the inside and outside diameters of the cup sides and not an actual bottom thickness, so I don't put much faith in them.

The drawings at the end of this report include one large rifle and one small rifle primer as well as a bunch of specialized ones. It certainly makes the specs look a lot tighter, at least for military gear.