Converting Percussion to Flint

[grabenkater]

A friend of mine is wanting to convert a CVA Hawkens from percussion to flint. In order to do this properly, he is needing a touch hole liner in 10mm x 1.25 mm per thread. Can anyone point me in the right direction for a supplier or someone who could make one?


Thanks!

[T*O*F]

In order to do this properly

The only way to do it properly is to obtain a flint barrel and lock.  Just removing the drum and screwing in a touch hole liner won't do it.  There are too many variables involved.  Just a word to the wise....nuff said!

[Dphariss]

I just did a conversion on a heavy bench gun its in the tutorial section.

Dan

[Captchee]

 Actually you can do it properly  just not optimally like a  blank barrel  and new breech would provide  . But it depends on what CVA you have .
 If you have an early one with the normally /common type  drum bolster then  all you need is a liner . But if you have the more common CVA drum bolster  then you have issues that have to be dealt with
 The problem you have to deal with is that CVA uses a very long  80% threaded bolster . As such you cant just thread in a liner without leavening a very large amount of threads exposed  inside the breech plug.
 If you do , these will build with fouling and  begin to  corrode  with carbonized fouling . Eventually this will start to effect   the  area of the liner .

So what to do ?
Well as was motioned , Optimally  and for best possible performance a new barel is the answer .
 The other option is to  pull the drum bolster .
 Check the  outlet to the main powder charge . In some case  CVA only made a slit  in this area , not a hole  that’s the same size as the flash channel . If you find that slit , drill the neck to have a hole .
.  Now re thread the drum bolster to the  breech  .
 Cut the drum section  off so as to leave the neck in the  breech .
 Now you can  drill and tap  the neck  so as to apply a 1/4,28 flash hole liner  .
 But only  drill and tap the neck no deeper then what’s needed for the liner
 You now have solved the issue with the threads. You have 5/8 of threading holding the sleeve into the barrel . The exact same amount as originally provided  for the percussion system  and you have  a flash hole liner that’s  faced to the inside shoulder as well as the  outer  shoulder .
 the sleve will be no more prone to coming out then  the original drum bolster was .
 the thing you dont want to do is use such a big liner that  you  get to thin of a wall  thickness  where you seat  the liner to the original neck .

So why is this less the optimal .
sometimes the inside of the original boster is just to  corroded to  be able to safly  apply a liner to . thus wall thickness becomes a concern .
 Also   since what you have is a patent breech  with a large  anti chamber it can be  troublesome to keep clean .
vs a true patent breech with a smaller flash channel  that goes to a larger antichamber .
 If the chamber also doesn’t fill with powder , you have a long distance  for the flint ignition to reach the main charge . IE a slow ignition.
VS a new barrel and breech that will provide  a much closer distance to the  main charge , faster ignition and less issues with  fouling  

[Glenn]

This is the first thing I ever considered doing to ML firearms and is what sparked my interest in wanting to build them from start to finish.  I was going to try a CVA conversion and I'm glad I researched it first and asked more knowledgeable folks a thousand questions.  What I arrived at is that if I wanted a flintlock weapon, I needed to change the lock and the barrel together.

CVA has a special breechplug/drum assembly and as far as I understand it is intentionally designed NOT to be messed with.  Safety first ... spend the money for another barrel and lock and match those 2 pieces together.  That way when you want to swap back and forth you have a lock and barrel perfectly matched of both ignition sources and you don't have to worry about your safety being compromised.

[Captchee]

 There is only  2 safety concern to deal with  concerning this conversion.
 The first is  really ones personal opinion concerning the use of a liner .
 The 2nd concern is as to if  there is enough  material left in the old bolster  neck wall  to  allow the liner to be threaded in and hold properly .
 If the existing bolster is in  good condition then  there is enough material , of proper quality to hold the liner in place . Unless one uses a liner that way to large
 No internal modifications to the breech or  the way the   original bolster is  threaded to the breech , have been or need to be changed .

 Here is alittle  knowledge for those  with little Jukar/ Adesa  experience .
 The parts for these guns are fitted by  friction machines.
 Basically what this does is the machine spins the part into place  . Think of it kinda like holding  the palm of your hand to a jar lid and trying to turn it , without gripping it .
  But the machine uses a lot more force   while at the same time using a stall so as to limit the torque applied . This is why you see no  notches  on the bolster  or for that mater the breeches"which also have a mm laper prior to setting  " which allow  you to apply a wrench to tighten . The machine doesn’t need them  .

 This is also why  concerning the breech  on factory breeched  barrels , why the can be such a bugger to get out  and often times even after pulling the bluster the plug threads get buggered up  either in the barrel or on the plug  . The pressure fitting expands the breech slightly  . Then the  bolster hole is drilled and threaded  which complicates removal even more   as that process can create a burr 
 This has been the standard of assembly for CVA , Jukar  and Traditions  thought their manufacturing .

 Thus in the early models with the short necked  drum bolsters , commonly used today by custom builders   . The  bolster was prone to backing out becouse its not fitted to the barrel  by the same process
 As such Jukar /Adesa  went to a longer threaded neck . This did not solve the problem  . Its seen every time you see an old CVA with  vice grip or pipe wrench marks around the drum..
 The early  bolsters again commonly used  still today even in the full custom  rifles  do  NOT tighten down  to an internal face . They tighten to the side of the barrel flat  the very same way as tightening a bolt  that’s threaded into a steel plate without a nut .
As such  the design was changed  so as to  provide an eternally mating surface  and not rely barrel flat alone  . Thus you see the longer necked bolster   with a mating face  that are used in these guns today ..

 Also for a time Jukar  was  using a mill process to  expose the  bolster flash channel  with a slot .  We have to remember that these guns were being made as cheaply as possible .The thought was that this would allow more threads  and increase the integrity of the bolster neck  while at the same time  serving the purpose of  allowing the  flash to reach the main charge .  But it also was troublesome because it  more easily fouled . So they went to a  milled hole .
Chances are if you pull the bolster  on a CVA your going to find a hole  in the bolster neck  that’s aligned with the main charge NOT a slit . But there are still guns out there with that slit . Just as there are still guns out there with the  short and medium necked bolsters .

Anyway . I submit this .
 By cutting the drum section off  and utilizing the neck , have we changed the way  the system has/was designed to seat . Nope  because it seats eternally and  your still providing that seat .
 Have we changed  the   amount of threads the design uses , nope .
 Have we made the design weaker  , nope
In fact what we have done is  marginally reduce the amount of pressure  that the  design may encounter because now its vented .
So again the only concern is IF one has enough meat  left ion the bolster wall to thread a liner to .

[Dphariss]

I do custom guns and I seat parts to a shoulder in almost every case.

The mass produced stuff, no matter who makes it is assembled so the parts will screw together with no fitting. "Tolerance" and a high torque capability is all that is needed.
Even the big name stuff has a significant fouling/oil trap in the breech.
Like this one sold by a big and old name in international gun making.

This was the upper end of the mass produced ML market. But still sloppily assmbled.

Another not so old but still big name in firearms machine installs breech plugs, or did, so tight they would often break off if removal was attempted.  This was a result of the torque applied and the high torque stretching the rebate (short cut in manufacturing) behind the threads so that it was already stressed near the breaking point in some cases. The breech pictured at least has no rebate behind the threads.
But they don't have the time or a workforce that can do the work and still sell the gun for what the usual Wally World gun buyer will pay.
Given the properties of some of the propellants used in MLs today I am constantly amazed that there have not been some corrosion related catastrophic failures of these things.
I won't have a mass produced gun in the shop.
I am rebarreling a custom built sometime back (Douglas barrel) by a well known name in MLing that had a very poor job of breeching and drum installation. Sure it worked and did not fail but that is not the point. The point is it should have been done right to begin with.
Far too many people just screw things together and let it go at that with no worry about fouling traps, fouling penetrating into the threads , gases leaking around the threads (these last two due to modern "tolerance" built into the taps and dies etc etc. Many don't even understand "fouling trap" which can result simply from tapping the hole for the drum so deep that threads are cut in the bore making a fouling trap. Relatively minor but still a fouling trap.
In some cases this is little more than an annoyance. But in other cases its a safety problem especially with the use of propellants with far more aggressive fouling than BP produces.

But fitting a breech, counterboring for  shoulder seal, cutting a proper nipple seat on a percussion breech etc takes time and the purchase of tools that that are not available at the local hardware store. So many just put the parts together as they get them and figure thats how its supposed to be not realizing the parts are just that and need to be properly modified and/or fit for any given application.
Dan

[Captchee]

cant disagree with you there dan