Difference between pistol and rifle primers

P

Prof Young

New member
Loaders:

So I've skimmed through the bazillion posts on here about primers. Lotta good info there. I'm still wondering . . .

What is the basic difference between a rifle primer and a pistol primer? I understand that rifle primers are generally harder than pistol primers (But why?) and what other differences, if any, are there?

Life is good.
Prof Young
 
Not a harder metal, but a thicker metal, for the cup in rifle. That is for the same "brand". There are of course brand differences between the metals. CCI is hardest, Federal is the softest. A Federal large pistol primer is the most sensitive and a CCI41 is the least sensitive. That sensitivity is more a scale as to how much force a given firing pin need to reliably ignite.

Glock strikers don't have a great footprint for primer ignition while the small (1.5mm) firing pin in a Large primer cartridge rifle has the best footprint.
 
Why?
Many rifle cartridges run a bit higher pressure than pistols so thicker cup is less likely to rupture on firing.

Semiautos can have issues with firing pins making contact with the primer in normal operation and a harder cup reduces chance of accidental ignition.
 
The primers must contain pressure ...there is a hole in the case (primer hole) that lets the pressure push against the primer and rifles generate (usually) more pressure than handguns ...thus the rifle primers are thicker than pistol .
If the primer backs out of the case it could cause problems with cycling of the action .
So normally you want primers to stay in the case be it rifle or handgun , higher pressure requires a thicker cup , lower pressure can use a thinner cup .

One rifle was actually designed around that principal ... the primer was designed to back out and unlock the action ( it may have been proposed during development of the M-1 Rifle)
 
Here is a page on using pistol primers in an AR15.
http://natoreloading.com/pistolprimersAR15/

You can use them, but you must lower pressure to near a pistol pressure. Because like MarkCO pointed out, the cup thickness is too thin, so they pop. Thicker is for more pressure. Different primer brands not comparable because they are using different metal composition....

Professional shooters complain about CCI rifle primers for example, because sometimes they don't go off in match guns when you pull trigger, because its too hard. I never had that issue, ever, but its one of those thing you hear because maybe some pro back in 1984 didn't have proper headspace or something, and it didnt go off.

CCI primers are hardest, but zero issues. You would think, after selling, literally HUNDREDS OF MILLIONS of primers, if there was an issue, somebody would be able to replicate it right?
 
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