Results 1 to 10 of 10

Thread: Firing pin diameter

  1. #1
    Join Date
    Feb 2006
    Location
    California...unfortunately
    Posts
    339

    Firing pin diameter

    Gentlemen,

    I just purchased an aftermarket, speedlock firing pin for a short action, push feed Model 70. Upon examination, I noted that the firing pin tip was .081 in diameter. That seems a bit large to me. The reference that I have calls for .075 max diameter in higher pressure cartridges (it's a .22BR). What do you guys think? Too big? Turn it down? Leave it alone? I will be bushing the firing pin hole, fyi.

    As always, thoughts and opinions appreciated.

    Justin
    Last edited by Zebra13; 11-07-2008 at 01:45 PM. Reason: uhhh...

  2. #2
    Join Date
    Feb 2003
    Posts
    144
    justin:
    I use .060 as the pin dia.

    Clarence

  3. #3
    Join Date
    Feb 2006
    Location
    California...unfortunately
    Posts
    339
    Quote Originally Posted by cdupuy View Post
    justin:
    I use .060 as the pin dia.

    Clarence

    Clarence,

    That is the diameter range I hear bandied about the most, hence my concern of the .081 diameter.

    Thanks,
    Justin

  4. #4
    Join Date
    Oct 2005
    Location
    Arizona
    Posts
    230
    Some replacement pins such as Holland's come oversize so you may fit them to your bolt pin bore. That may be why yours came so large. If you are going to bush your bolt it seems .060 is the preferred size these days.

  5. #5
    Join Date
    Feb 2003
    Posts
    1,868
    On a hunting rifle it won't matter.

    If you decide to make it smaller, don't turn it down, accurately grind it down a thou smaller than your bushed hole.

  6. #6
    Join Date
    Feb 2006
    Location
    California...unfortunately
    Posts
    339

    Bushing material

    Gentlemen,

    What are you guys using for bushing material?

    Justin

  7. #7
    Join Date
    Feb 2003
    Posts
    511
    I used 4140, had some 1/4" diameter rod. Bushing was 1/8 o.d., 1/8 long.

  8. #8
    Join Date
    Feb 2006
    Location
    California...unfortunately
    Posts
    339
    Quote Originally Posted by Jay, Idaho View Post
    I used 4140, had some 1/4" diameter rod. Bushing was 1/8 o.d., 1/8 long.

    Jay,

    Was it heat treated, and if so, to what hardness? The only thing I have laying around right now is drill rod. Could that be used?

    Thanks,
    Justin

  9. #9
    Join Date
    Feb 2003
    Posts
    511
    Quote Originally Posted by Zebra13 View Post
    Jay,

    Was it heat treated, and if so, to what hardness? The only thing I have laying around right now is drill rod. Could that be used?

    Thanks,
    Justin
    It was pre-hard 4140 from Aircraft Spruce or Nolan Metals. I'd use drill rod but would not hear treat it. I see no reason that it needs to be hard. It supports the primer cup, that is all.

  10. #10
    Join Date
    Feb 2006
    Location
    California...unfortunately
    Posts
    339
    Quote Originally Posted by Jay, Idaho View Post
    It was pre-hard 4140 from Aircraft Spruce or Nolan Metals. I'd use drill rod but would not hear treat it. I see no reason that it needs to be hard. It supports the primer cup, that is all.
    Jay,

    I was going to bush the bolt a la Borden, which has the bushing extending out beyond the primer cup, so I'm a little concerned about the hardness. I could just order some pre-hardened 4140 and be done with it, but I was trying to find something available locally, or that I already have. Would a Grade 8 bolt, machined to make a bushing, be suitable?

    I was looking at an Aircraft Spruce catalog for the first time yesterday...all kinds of goodies in there!

    Thanks,
    Justin

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •