Tuesday, February 10, 2009

Resealing the Smith and Wesson Model 79G, Addendum

I noticed that some gas was coming out of the breech when firing, bypassing the bolt. Then I remembered that I had not changed the bolt o-ring! I didn't want to tear the pistol all the way down again so I decided to replace the o-ring in place.

The bolt open.

Two dental picks carefully extract the o-ring.

The o-ring removed.

New o-ring on the left, slightly larger.

Massaged back into place. I basically got it halfway on and then closed the bolt which seated it.
Now the bolt does not show evidence of allowing gas by.
at

3 comments:

  1. AnonymousAugust 19, 2009 at 1:15 PM

    By the way - what diameter have these seals ... if you remember please give more info! Thank you!

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    Replies
    1. AnonymousJuly 4, 2025 at 6:14 AM

      This is o-ring with BS-ANSI Number 005, or CS 1.78mm ID 2,57mm OD 6.13mm see also https://www.allorings.com/British-o-ring-Size-Chart The other O-Rings you will need are the sizes 006, 012 and 113

      Delete
  2. Felice LuftscheinAugust 19, 2009 at 3:32 PM

    I don't remember, but you should be able to just reverse engineer the dimensions from the valve.

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