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Thread: Why..................?

  1. #1



    CYA friends:

    Since we're about to get the MD-PAS triple, for the masses, that we must have to advance rimfire accuracy past where we're at today, and since we're exploring MD-PAS verses any form of SAP ignition, I'd love to know a "why" about something.


    Back when I converted XP's to 22 LR, and when I would develop my ignition, here's the way I went about it:

    I'd fire some rounds in my bucket, and save the empties to re-use to develop my ignition, which included locating the firing pin footprint in the proper location.

    What I'd do, to keep from having to fire so many rounds in my bucket, would be to turn one of the empties up-side-down, then close the breech bolt while pulling the trigger, so the firing pin would rest against the case head.

    Then I struck the cocking piece lightly with a little brass hammer, which imparted a footprint in my empty case head.

    And then I'd adjust the footprint location accordingly, etc.

    But right off the bat I made an interesting discovery.

    At first I left the firing pin spring out, with the breech bolt fully assembled otherwise.

    But I discovered, that when I adjusted my footprint location doing it this way, no spring, when I reassembled the breech bolt and fired a live round in my bucket, the footprint location changed.

    So I quickly learned that I had to have a firing pin spring in the bolt, to guarantee the footprint I got, by using my little brass hammer, remained the same when I live fired the action.

    I found I couldn't easily do this operation with a full spring in the bolt, so I made up a short spring that just tied the ignition components together and it worked just fine thereafter.

    And from then on I got along just fine doing this, saving a lot of shooting in my bucket, which is noisy and wastes ammo.

    Now here's the "why" I'd like to know:

    How come I can develop my ignition, and footprint location, in MD-PAS actions, without needing a firing pin spring, shortened or otherwise?

    And the live fire footprint location is the exact same as the one I obtained with my little brass hammer?

    But with SAP ignition, I found I had to have some semblance of a firing pin spring in the bolt, before the live fire footprint would be the same as the one produced with my little brass hammer?


    Your friend, Bill Calfee
    Last edited by Bill Calfee; 12-05-2018 at 06:29 PM.

  2. #2



    CYA friends:

    Why can I blueprint the ignition of a MD-PAS action, like I do, without a firing pin spring in the breech bolt...........and be successful?

    But, when I blueprint a SAP action, why do I have to have some semblance of a firing pin spring in the breech bolt, before I can be successful?


    Hey, help me here, if you can, to understand this, please.

    Your friend, Bill Calfee
    Last edited by Bill Calfee; 12-07-2018 at 05:07 AM.

  3. #3
    Spring is guiding/centering pin of sap.

  4. #4

    Friend TE

    Quote Originally Posted by Todd Earhart View Post
    Spring is guiding/centering pin of sap.

    Friend TE:

    Thank you.

    You know, back in the 80's, well before Flash Ebert brought out his MD-PAS ignition Turbo action, I accidentally stumbled onto the reason PAS rimfire ignition, when well blueprinted, produces better consistency than any form of rimfire ignition where the firing pin passes through a coil spring.

    Back then, of course, I didn't know I had accidentally stumbled onto the reason for the consistency of MD-PAS ignition.

    All I was trying to do back then, was keep down the noise and save ammo......I was flat broke back then, and ammo was expensive.

    Actually, I've carried that concept on until today, since I'm still flat broke and ammo is still expensive.

    SAP ignition had to have that spring to hold all the ignition parts together, which includes loading the threads of the bolt shroud to the threads of the breech bolt body, and if correctly made, centers them to one another.

    There is no threaded bolt shroud, or threaded breech bolt body, or anything to center, in the very simplistic PAS ignition system.

    SAP ignition has a bunch of components that have to line up someway, somehow, perfectly, to produce consistency.

    Your friend, BC

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