Firing pin face shape ?

[jimbo_10x]

I have a 700 rem . 6.5x47
Occasionally I have trouble with pierced primers (CCI 450) on rounds that are not showing any signs of pressure . I would consider some even mild loads .
It has a aftermarket oversize pt&g firing pin in it but the tip looks pretty round .
In everyone's opinion what is the best shape for the firing pin face ?

 

[PatMiles]

Take a good look at the tip with a magnifying glass. Once they start piercing primers the tip starts getting eroded. Replace if necessary.

 

[Bill K]

Instead if it being the shape of the firing pin, it may be the type/brand of primer. Are you using one with a thicker cup, which will aid in stopping pierced primers with near max or high intensity cartridges ?

 

[jimbo_10x]

They are CCI 450 primers , they should be hard enough .
It has less than 500 rounds on the pin , it shouldn't be eroded .
Should it be completely rounded or have a flat on the tip .

 

[jimbo_10x]

Found this link https://www.milsurps.com/showthread.php?t=49179

 

[D-4297]

Next obvious question should be . Are you getting any kind of a ring , or burr around the F/P penetration radius ? I'm thinking maybe Bushing wear , and a re-bushing job in order . Is the F/P centered on the primer , or off-centered ?

 

[Terry_M]

If the loads are too light the case might not grab the chamber. Not enough info yet.

 

[swd]

Unless the loads are super hot 98% of all primer piercing problems are either sloppy pin fit or large diameter pins or both. Get it bushed and turned down to .062” if it’s not already.

 

[Terry_M]

Or grind some off the top of the pin. It's just a metal pin. Just go in little increments because theres no way to put it back if you take too muc .

 

[Scott Harris]

The 6.5x47 is a high pressure cartridge and is notorious for piercing primers in Remington 700 actions which have sloppy large firing pins. You pretty much have to get your bolt bushed/firing pin diameter reduced if you want to shoot the 6.5x47. Gre-Tan is one of the smiths that bushes bolts in volume.

 

[swd]

Or grind some off the top of the pin. It's just a metal pin. Just go in little increments because theres no way to put it back if you take too muc .

Please don’t do this. Long pins are pretty much never ever a problem. You won’t fix the problem and will just end up buying a new pin with the same problem. Also pin tip shape is very important and doubtful you’ll get it correct if you don’t know what your doing.

 

[Scott Harris]

listen to swd! There is no such thing as a firing pin that is too long. The primer stops the travel of the pin...regardless of how long it is. The geometry of the pin tip has a huge effect on whether it pierces. Simply filing it down ruins the geometry and thereby ruins the pin. Since you have already pierced a few primers,your best bet is to replace the pin and then send the bolt and pin in to get bushed by a competent smith.

 

[Terry_M]

Grind IT!!! If you're seeing a repeated issue and you are competent to measure protrusion then you know if it is in fact too long. If it's too long then make it shorter.

 

[tomswede]

A firing pin is supported have a spherical end. Don’t mess with that. Most actions have a positive stop limiting the protrusion. There is a value for that, don’t have it handy.

 

[swd]

Grind IT!!! If you're seeing a repeated issue and you are competent to measure protrusion then you know if it is in fact too long. If it's too long then make it shorter.

Please tell us how much protrusion is too much and what the recommended amount is.

 

[Terry_M]

Please tell us how much protrusion is too much and what the recommended amount is.

About an inch aught to do!

I prefer .0030, but will live with .0025 Only ever had to grind one and it was .0045 That was on a wildcat AR though and the protrusion was related to the machining of the bolt.

Why are you asking me anyway? Google exists for a reason.

 

[swd]

About an inch aught to do!

I prefer .0030, but will live with .0025 Only ever had to grind one and it was .0045 That was on a wildcat AR though and the protrusion was related to the machining of the bolt.

Why are you asking me anyway? Google exists for a reason.

As I suspected. Thank you.

 

[Old Navy]

I have a 700 rem . 6.5x47
Occasionally I have trouble with pierced primers (CCI 450) on rounds that are not showing any signs of pressure . I would consider some even mild loads .
It has a aftermarket oversize pt&g firing pin in it but the tip looks pretty round .
In everyone's opinion what is the best shape for the firing pin face ?

Do you have the original pin to put back in? I had my Remington bushed and my Savage BR. They both cratered primers. The Remington was so bad I couldn't slide the case in the shell holder. Both cratered primers but never ever blew one.

 

[Terry_M]

As I suspected. Thank you.

I suppose you were looking for me to say that most modern rifle are .055 and that there could be issues with fail to initiate if they are shorter.
What would that have proved?

If the OP has the ability to measure and their protrusion is beyond .060 then they should reduce that. There's no good way to add metal to the bolt face, so shorten the pin.

 

[swd]

I want the guy to fix his problem without creating more. His most likely problem is firing pin fit and or size, not protrusion. But it does need to be diagnosed to fix the right problem the first time. And with sloppy pins being such a common problem when guys go very high pressure cartridges like the 6.5x47 and all the 6BR variants I’d bet a good dinner firing pin fit and size is the problem. I’ve just seen it over and over so many times. Shortening the pin is akin to having a car that misfires at 4000 rpm so you put a throttle stop on it at 3500 and call it fixed.