CVA

[Captchee]

Sorry Typing on Laptop

[doc623]

Thanks for the help.
When you say short,medium, or long boister could you give me some specifics as to length.
I could take mine out and measure it but I still need a more specific reference.

[Captchee]

Thanks for the help.
When you say short,medium, or long boister could you give me some specifics as to length.
I could take mine out and measure it but I still need a more specific reference.

 no not really because they change in length depending on caliber
 So here is what I have done . I have  a medium , a small and an original .
 I don’t have any longs because I cut those off , then drill and tap  for a liner .
 So to show you the long , I have done a quick photo shop ..




CVA  at that time were having some issues

 So now the original .
 These are found on early CVA  rifles .  Early 1970s
 These thread in front of the breech plug ,,OR,,, split the face of the plug .
 
So they went to the small bolster with a bigger neck . To top it off they leaghtened the breech plug and counter drilled it ,,“IE improved  breech “
  This was to give the bolster more to  thread into
This however did not solve the issue
So they went to a  medium . This plug had a faced end that mated to the off side of the chamber in the plug
 This solved  some of the issues  .  But they took it all another step  and tried the long bolster .  This has a longer threaded end that  goes all the way through the plug and mates to the inside of the  off side of the barrel
This however did not work any better then the medium . As such  you mostly will find mediums  on the newer CVA rifles

 So why the need . Well as I said  CVA was having issues with bolsters coming out and loosening up . Im sure we all have seen  bolsters on CVA rifles and pistols that look like someone has taken a pipe wrench to them ,,,, right …….
 The problem wasn’t the bolster design . As you can  see the first two bolster look just like what you would find  on any  semi or custom rifle , that employs a drum type bolster .
Mind you a design that’s been around for as long as percussion guns .

 The problem lies in the way the bolster was set .
See  part of the manufacturing process that Jukar was using  and still uses , is that they use  friction tools  to set the bolsters and  hydraulic applications to set the breech ..

 If you notice  the bolster has no flats on them  like a bolster you would buy from a  supply  house .

well the original does . but i filed those , long ago

So  once the  bolsters were place , they were not as tight as they should be .
 The bolster is then indexed , drilled an tapped for the nipple .
 Then set aside to go on to assembly.

 But because the bolster  wasn’t tight . As soon as the rifle was subject to regular firing , it would work itself lose . People would then  try to tighten it up . But they couldn’t because as soon as they tightened it to wher it should be , the nipple would no longer align.
 If left miss aligned . The hammer would eventually loosen the bolster back up   .
To top that all off , fouling would get into the threads , eventually corroding them   to the point that the bolster would blow out
 Hence the evolution of the longer necks .

 Basically if the need was to ignite  pellets  in the center , which is  a better way to ignite all powder , not just pellets “ hence the true thought behind the improved breech designs “
 There  would be no need for the longer  neck bolster . A short bolster would do the very same thing when threaded into an improved breech

[doc623]

Thanks for the help.
I'll have to check mine.
Don't know the year of mfg.

[doc623]

Upon closer inspection it appears to be a 'Silver Eagle'.
Stone Mountain mfg.
The bolster measures 0.540" long and 0.492" in diameter is that is any help.

[Captchee]

what you will need to do is compair the leaght of the neck on the bolster , with the  barrel wall thickness  where the bolster screws in . if its the same , then you just need to replace the  bolster with a liner  and add an appropriate lock .
 if not then all the past wordingf still applies

[doc623]

Thanks.
What would be the best way to remove it?

[Captchee]

if the bolster doesnt already have them , you need to file ywo flat spots  on each side so as an open end wrench will fit  properly .
" see my photos of breech plugs "
 then simply  turn it counter clockwise .