What's all about pierced primers in O/U?

"Quote Chilly807":::

I have dressed the tips of shotgun firing pins a couple of times. Like yourself I have used a fine stone & the pin turning in the bit of my drill press.

As you suggested, go slow & check the protrusion, hard to replace metal once it is gone.
 
http://www.sharpeningsupplies.com/What-is-a-carborundum-Stone-W25.aspx


Lol.. mine was old before the internet ever came on the scene. This link shows what they are, but mine is much smaller, about 1" wide x 4" long x 1/4" thick.

You want a fairly fine grit, but not to the extent of it being an Arkansas stone. Those would work, and are good for a final polish, but actually removing any material with an Arkansas stone would take a long time.

Someplace like Home Hardware should have them, Busy Bee or Lee Valley definitely should. Your grandfather probably used one to sharpen his pocket knife. I'll post a pic of mine later today to give you an idea of what I use.

What kind of gun are you dealing with?
 
Not mine but some good info here IMO

A number of years ago Browning acceded to the complaints of gun buyers that the over barrel firing pins were too short to light some European primers given the severe downward angle at which the pin strikes the primer cup. Browning made the pins .010" longer and changed the nose profile from a pan shape to a half sphere. Now the longer pins are punching small holes in the steel cups of some primer primer brands which causes the burning and pitting some reloaders experience when using these primers.

Other that switching to better primers with brass cups instead of steel ones, the quickest fix is to remove the firing pin that's been burned, chuck it in a drill press or lathe and stone the nose of the pin smooth to remove the pits shorten the pin and make the nose more blunt like the earlier pins. It's also possible to simply switch to the earlier under barrel firing pin if you can find a gunsmith who still has some. I built a jig to hold the pins so they can be measured accurately with a vernier caliper.

The old style pins measure ±1.195" overall while the revised pins measure ±1.2095" overall. Browning's tolerances for total under barrel pin protrusion is .050"-.070". This can be measured ONLY when applying pressure to the hammer end of the pin to push it forward against the end og the pin bore; otherwise the pin return spring will be pushing the pin back against the hammer face and measurement at the breech face will come up short.
 
3macs1 said:
Not mine but some good info here IMO

A number of years ago Browning acceded to the complaints of gun buyers that the over barrel firing pins were too short to light some European primers given the severe downward angle at which the pin strikes the primer cup. Browning made the pins .010" longer and changed the nose profile from a pan shape to a half sphere. Now the longer pins are punching small holes in the steel cups of some primer primer brands which causes the burning and pitting some reloaders experience when using these primers.

Other that switching to better primers with brass cups instead of steel ones, the quickest fix is to remove the firing pin that's been burned, chuck it in a drill press or lathe and stone the nose of the pin smooth to remove the pits shorten the pin and make the nose more blunt like the earlier pins. It's also possible to simply switch to the earlier under barrel firing pin if you can find a gunsmith who still has some. I built a jig to hold the pins so they can be measured accurately with a vernier caliper.

The old style pins measure ±1.195" overall while the revised pins measure ±1.2095" overall. Browning's tolerances for total under barrel pin protrusion is .050"-.070". This can be measured ONLY when applying pressure to the hammer end of the pin to push it forward against the end og the pin bore; otherwise the pin return spring will be pushing the pin back against the hammer face and measurement at the breech face will come up short.
Click to expand...

Now that right there is interesting information! Thanks!
Buying better primers to reload with wouldn't bother me so much, I did it with my 725 for a while until I got fed up and fixed it. Well, I should reword that. I don't like spending more than I have to when the Cheddites are fine otherwise.
Even buying factory ammo becomes a problem when all that's easily available is Cheddite primed, such as Challenger or Estate.
 
Thanks everyone. That is some good info. One of my 725s is piercing on the lower barrel. The other one runs without issue. I will pick up a spare firing pin and try to reduce its length slightly. Anybody know where a guy can get replacement firing pins? Brownells seems to be out of the lower at the moment.

Thanks,
Cal.
 
You have an ideal situation, believe it or not. What I would do in your place is pick up a digital vernier to measure the firing pin protrusion on both guns. You'll need to remove the butt stock to do it. Press the lower pin firmly forward (it's lightly spring loaded) and measure how much of the pin sticks past the breech face. If you get slightly varying measurements take the average of 5 measurements.
Start with the "good gun". Then compare those results to the problem one.
If what we've discussed is causing the issue, the problem gun's lower firing pin should be protruding somewhat further than the good gun's. If it isn't, then something else is causing the problem, possibly a rough surface on the pin, etc.
If you do decide to shorten the pin, don't simply make it the same overall length as the good one. The critical thing here is how far it sticks past the breech face. There may be some variation in the thickness of the breech face between the two guns, which will influence how long the pin needs to be to stick out "x" thousandths of an inch. Try a small change first, 0.005" shorter might be enough to do the trick. If you go too far, you'll get fail-to-fires. Mine seemed to work ok at 0.052" protrusion.

One more thing. The FP retaining pins on your Browning are small straight pins with a serrated head on one end to hold them from shifting. Pick up a cheap jewelers eye loupe and look closely to see which end is which.
Only drive them out one way, in other words tap on the non-serrated end, so the serrated end comes free first. Put them back in the same way you found them, and either take pictures or make careful notes as you go so you don't forget which way they were.
Don't ask how I know this.. lol.
I got mine from Brownells, it was an ordeal dealing with UPS. I'd order them through a gunsmith if I had to do it again, or Browning Canada if they will sell them.
 
Thanks Chilly, that's some great info right there. To revive this thread, I've finally got around to sourcing replacement firing pins and will be giving this a try in the near future.

Thanks,
Cal.
 
Hopefully it'll work for you, it cured mine. It's a "perfect storm"situation. The Cheddite primers are prone to piercing under the right conditions, and the Browning firing pins (among others) provide those conditions. Remove either element and the problem goes away.
 
All I used was a carborundum stone, like you would sharpen a knife with. I may have used a fine Arkansas stone to finish the job, but can't remember for sure.
You don't need a mirror finish on the end of the pin, but it should be smooth. Look at the ends of the new pins when you get them, that's what you're aiming to duplicate.
 
Hi Chilly,

Nothing yet. Life got in the way. I have my spare firing pins and replacement springs all ready to go, and have this stone on order from Amazon. I hope to get to it this weekend or next.

amazon.ca/gp/product/B00F73BPFE/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Thanks,
Cal.
 
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