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Firing pin for the VG1-5

With there not being any parts available we have to design and make every part. Some times this leads to re-doing a design several times. The firing pin is a case in point.

The initial design was to use a H&K 91 firing pin that was turn down to fit the VG1-5. The reason for this  is that I have a number of them in stock and it is already of the proper material and heat treated. However, it actually  takes more machining steps to make it this way then making a new one. The other problem is that it would only leave a small area at the rear of the firing pin for the hammer to hit. The design of the rifle required a much larger area, height of the hammer and location of the firing pin in the bolt.

IMG_2259s

The next idea was to use a 1911 firing pin. We seriously looked at this idea, but there were still some design set backs as well. I would still have to machine it to fit properly and I would still have to make the other half of the firing pin, but at a much small size.

IMG_2260sOriginal design for second part of two piece firing pin.

IMG_2261s

IMG_2262s

The third and final design was to just design and make a completely new design. So, that is what we have done. The initial 5 are made in 4140 that will be heat treated. If after testing  they hold up and we have no problems we will make the remainder. If not we will be changing the material specs.

IMG_2263s

Here is a solid model of what the firing pin should look like in the bolt.

FIRING PIN ASSEM2smallAnd another view.

FIRING PIN ASSEM1smallNeither of these show the spring. A final solid model.

FIRING PIN ASSEM8smallThe notches have not been cut into the rear portion of the firing pin yet. Still working on the design of the fixture for that.

7 comments to Firing pin for the VG1-5

  • Marko

    What is the purpose of the notches? I am not at all familiar with this firearm. Just curious. Nice!

  • juver

    i like the X-Ray cat pictures
    what other things have been redone or have been re design ?

  • Glad to hear that the project is still moving along. As you noted it requires a lot of thought process to come up with solutions to what seem like simple problems but are not. Looking forward to more. Harry

  • John D.

    German WW II metallurgical practice for firing pins was usually DIN C20 (AISI/SAE 1018, more or less) steel carburized. This is not especially practical for short run production. Developing a successful carburizing technique requires a lot of trial pieces.

    I have made replacement firing pins for WW II MG.34s and P.38s, which have fragile firing pins, from AISI Types S5 and H13 tool steel. Heat treatment is easy: austenitize, air quench, and double temper. You can cryogenically treat and add a temper if you want to get fancy. Air quenching minimizes distortion, which may be the reason you are trying to adapt an existing, already heat treated, firing pin. The resulting firing pins are extremely tough and require no clean up after heat treating.

    AISI Types S5 and H13 are too expensive for production gun firing pins, but they work well for ‘one offs’. Some of my friends have used AISI Type 410 stainless steel, but I don’t know how well this has held up – no feedback.

  • John Petrie

    Chuck,

    How much more time is the VG1-5 going to take?

    John Petrie

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