Should I change primers?

[MOA]

I've noticed the regular large rifle primers really getting hammered in my sporterized swede 50 cal rolling block rifles. I'm pretty sure it is the protrusion length and possibly the shape of the firing pin. Also it might be that the original primers that were used in these old military rolling blocks had a very different type of metal and a thicker/harder material. I haven't had any pierced primers yet, but I would like very much not to have one in the future either. I have been thinking of trying some of the CCI #34 primers I have that I use in the sks ammo. Anyone else come across this type of issue, and if so what did you do?

[waksupi]

If the primers aren't getting pierced, I wouldn't be too concerned. My Trapdoor puts a real divot in primers, no problems.

[MOA]

waksupi,
I'll have to see if I still have any cases that I have not already de primed and take a image of it to post. It is a real as you say divot.

[turtlezx]

why not shorten the pin?

[Winger Ed.]

CCI #34s are supposed to be a little thicker. If its handy, try 'em.
I use them loading for a M1A. Compared to others, they do seem a little tougher and show less pressure signs.

[MOA]

Thanks for all the suggestions. I'll try the #34's first, and then I will see about regrinding the pin, wouldn't want to grind it too short, it's not like you find these firing pins at your local gun shop if you screw it up.

[Baltimoreed]

Anyway you can lighten or swap out [for a lighter one] the mainspring? I wouldn’t mess with the firing pin. If its a flat spring you might add a piece of thick leather between the spring and frame at the screw and leave the screw a little loose. Change the angle of the spring in relation to the lower tang to make it flex differently and it should have less umph which should put less umph to the hammer. Of course those big hammers on rolling blocks [had a couple] aren’t 1911 hammers.

[earlmck]

More likely your issue is from the old black-powder firing pin -- large firing pin hole, large firing pin, enough pressure to push some primer material back into the pin hole. All this makes a rasty-looking primer. Remington primers are also made of tougher stuff: I have an old Sharps-Borchardt/22 hornet for which I use the Rem 71/2 primer for its toughness to avoid pierced primers.

Oh yeah, I shortened the firing pin in the rifle before I figured out it was not the length of the pin that was getting me, it was the diameter of the firing pin hole. Fortunately I still have enough pin left to get the job done, but shortening the pin didn't help one single bit.

[country gent]

Changing the primers may get you by for now and may work good. But in all honesty I would recommend having the one bushed and pin shortened and modified so any primer works safely. In the long run this is the better option. The old rollers Sharps and heavy hammers and springs really delivered a heavy blow to the pin and primer

[egg250]

Is it just that the divot seems to be deep? Any cratering? Measure the positive firing pin protrusion. Positive protrusion is how far the firing pin sticks out when the hammer is fully forward. It should be no more than .050". Don't go grinding on the firing pin. You'll shorten it too much and ruin it. If it is too long you'll want to shorten it using a file. Determine how much length you need to remove and take a few file strokes at a time, checking length. Once you get it close to size, within .003" or so, round the corners to form the dome shape and finalize the size.

My opinion, you haven't experienced any pierced primers, you'll probably find the firing pin is the proper length. This is a low pressure cartridge? Higher pressures generally lead to flatter primer dimples.