From: John De Armond
Newsgroups: rec.guns
Subject: Re: Snap caps and brass
Keywords: dry firing
Date: 6 Mar 89 18:20:21 GMT

I've been using very simple to construct snap cap for dry firing for
many years.  They are made as follows:

*  Take empty brass for the weapon of interest and remove the
   primer.

*  Fill the primer pocket with ordinary Silicone RTV bathtub caulk.
   Wipe the surface flush with the rear of the case with a wetted
   finger.

*  Let the RTV cure.

These are very durable, especially the caulk (as opposed to the adhesive)
RTV.  When one finally wears out, all you gotta do is ream the old stuff
out and replace - or just throw the case away.

John

From: bercov@bevsun.bev.lbl.gov (John Bercovitz)
Subject: Re: The other side of Snap Caps
Organization: Lawrence Berkeley Laboratory

In article <37866@mimsy.umd.edu> ut-emx!lizard@emx.utexas.edu 
(Tom Linsley) writes:
#There's been some talk of snap caps here recently, and I thought I'd put
#in my (disgruntled) two cents' worth.
[stuff deleted]
#but one day I came across some snap caps in the local gun shop and thought,
#I need to get some of these to protect my guns.  I picked up a 6-pack of
#38/357 caps to try out; they set me back around $16-$17 as I recall.
#These were of Italian manufacture, with a transparent plastic body and red
#"head".  The "primer" was a brass insert which worked against a spring
#within the body.  All in all, they looked to be quite well-made and of
#high quality.
[stuff deleted]
#After a few minutes, however, I noticed that the back of
#the gun was covered with brass swarf.  Evidently the hammer had chipped
#away at the brass "primer", and the chips and dust had made their way

I've had the same problem with these snap caps.  However, since I use them
in a government model, the brass dust isn't too debilitating.  Furthermore,
the government model really _should_ have a snap cap.  Have you ever checked
how far out of the breech the hammer throws the firing pin?  Must be damn 
near half an inch.  What stops it is the firing pin's return spring's coils
bottoming out against each other.  And that kind of bothers me.  I don't
think a good modern S&W or Colt revolver really cares if you dry fire it 
or not.

I've seen snap caps for shotguns which have a hard plastic piece where these
snap caps have brass.  Has anyone seen snap caps constructed like this except
made for the 45 government model?

        JHBercovitz@lbl.gov    (John Bercovitz)

From: bercov@bevsun.bev.lbl.gov (John Bercovitz)
Subject: Re: The other side of Snap Caps
Organization: Lawrence Berkeley Laboratory

In article <37905@mimsy.umd.edu> les@ulysses.att.com 
(Leslie Johnson[cwc]) writes:

#Speaking of snap caps and dry-firing rimfires;  I'd like to be able to
#dry-fire my Ruger MarkII without fear of dinging the chamber or
#whatever.  

If your Ruger Mk II 22 auto hasn't been modified, the firing pin tip
can't reach the chamber face.  The firing pin's forward motion is
stopped by the bolt's crosspin.  It's easy to check that the parts
work properly: remove the bolt from the gun, push the firing pin forward,
note that the pin's tip does not protrude as far the the frontmost plane
of the bolt.  This frontmost plane is what stops against the chamber face
so if the firing pin doesn't stick out that far it can't reach the breech
face.

        JHBercovitz@lbl.gov    (John Bercovitz)