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Thread: Firing pin protrusion

  1. #1
    Join Date
    Apr 2003
    Location
    South Australia
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    159

    Firing pin protrusion

    What is considered to be the maximum firing pin protrusion for a Remington bolt?
    A friend has a Rem 700 in 22 PPC and it occasionally punches through the primer. The load is below maximum.
    The action (Rem 40XBBR) has been blue printed and a smaller firing pin (0.064) fitted.
    As near as I can measure it there is 60 thou pin protrusion.
    A visual comparison to my Stolle and BAT action shows that the Rem is sticking out more.
    Comments please?

  2. #2
    Join Date
    Feb 2003
    Location
    Houston, Texas
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    7,997
    Quote Originally Posted by B J Atkinson View Post
    What is considered to be the maximum firing pin protrusion for a Remington bolt?
    A friend has a Rem 700 in 22 PPC and it occasionally punches through the primer. The load is below maximum.
    The action (Rem 40XBBR) has been blue printed and a smaller firing pin (0.064) fitted.
    As near as I can measure it there is 60 thou pin protrusion.
    A visual comparison to my Stolle and BAT action shows that the Rem is sticking out more.
    Comments please?
    BJ, in my experience, .065 is the limit, .055 about perfect.

    I think a lot depends on the amount of actual spring pressure as well. Logic would dictate a weaker spring would not tend to drive the pin all the way trough. A smaller pin has less area of contact to buffer the hit.

    I think the best thing to do is dress it back to .055 and see if that cures the problem. Be carful dressing it back. You do want to maintain a convex shape, but avoid letting the convex protrude back into the hole.

  3. #3
    Join Date
    Oct 2019
    Posts
    497
    just because the load is "below maximum" is no proof
    that the firing pin is the issue.
    primer issues are "normally" a load issue.

  4. #4
    Join Date
    Feb 2003
    Location
    Fresno
    Posts
    5,567
    If you do some measuring of the distance from the back of the shroud to the back of the cocking piece, using the bottom of a caliper, comparing the fired position with an empty chamber, vs. the same thing after firing a primed case I think that you will find that the firing pin is stopped by the primer, quite a bit short of full protrusion. Longer protrusion decreases the total fall to where the primer stops the pin, which decreases the energy delivered to the primer. I would check the shape of your pin tip, and also the cocked weight of your firing pin spring. The detent (made by the pin from firing) in the primer cup is supported by the inertia of the pin and the strength of the spring. I would be more concerned about a weak spring than one that was stronger than factory. Also, I ran into blanking for my PPC when fire forming cases that were not a snug fit at the neck shoulder junction using 205 primers. I may not have had the bullets seated long either. Switching to harder primers for fire forming solved the problem. Later I was more careful about seating depth and how far I cut into the shoulder when turning, and the problem did not repeat. One result of the blanked primers was a fire cut across the tip of the firing pin, which would have been a problem causing primers to be cut. I stoned the tip to remove it.

  5. #5
    Join Date
    Jul 2005
    Posts
    613
    Quote Originally Posted by B J Atkinson View Post
    The action (Rem 40XBBR) has been blue printed and a
    smaller firing pin (0.064) fitted.
    Was the bolt bushed and re-bored for the smaller pin?
    It sounds like there is excessive clearance around the pin.

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