an old CVA derringer kit

[shermo]

Many years ago I bought one of the CVA 'derringer' kits, and laid it away (i.e., lost it). Recently it turned up, and I started building it.

I have a bit of experience, but all of it is quite long ago. I built a by a 'Kentucky' pistol (caplock) from a kit. Then, under guidance from an experienced builder, I did a Pennsylvania flintlock (early 1800 style) from parts -- no kit.

Both of these projects turned out very well. Then I got busy raising and supporting a family, and built no more Now, however, being retired and my family grown and gone, I want to begin again. The CVA derringer kit was easy, and went quickly. BUT...

The hammer seems to lack enough force to pop the caps! At least, that's my best guess. It goes clunk on the cone, but the cap stays inert.

I probably should just give up at this point, but before I do that I thought I'd ask the experienced builders in this forum if they have any suggestions as to what I might do to 'debug' this project and get the pistol shooting.(?) I really hate to leave it unfinished, if there is anything I might do to rescue the project.

Thanks for any help or advice.

Shermo

 

[ryzman]

I would try a different nipple as the one that came with my gpr kit was garbage... had the same symptoms as you described. might want to try that first as its cheap and easy to replace.

 

[necchi]

1st thing I'd do is fully disassemble the lock, degrease it and check for burrs or rough edges on the bearing surfaces. A little polishing can go a long ways, I actually use a fine India stone made for sharpening knives.
CVA didn't spend alot of time doing finish work on the "stamped" parts.

If it was stored all those years with the hammer cocked the main spring could have lost it's tention. A replacement can be had for around $12-15.

An Welcome to the Forum. You've found the right place. :hatsoff:

 

[rafterob]

The CVA derringer I had also had a week mainspring. If I pulled the hammer all the way back (past full cock), pulled the trigger and let the hammer go it would fire every time. It would rarely fire from the full cock position though.I just got used to firing it that way and never bothered solving the problem. It might be worth a try to call Deer Creek and see if they have replacement springs for that lock.

 

[Zonie]

The first thing I would do would be to remove the lock and give all of the moving parts a good shot of oil.
That includes the area under the tumbler and hammer.

Often, old oil or grease down in the working parts drys out over the years and works to stiffen up, rather than lubricate the parts.

 

[jdw276]

check the screw that holds the lock. if silver on the end its to long and slows the lock. grind off the end a bit to shorten.

voice of experience on that issue!

 

[Rifleman1776]

I used to sell those in my shop. Your experience is common. The old CVA springs were often weak. There is a trick, not gunsmith approved 'technique' :shocked2: , that usually works. With the mainspring relaxed, like out of the lock, just wedge a hunk of leather into the inside 'V'. That will change the geometry of the spring and give it greater force. Please note: I did say "usually works". When it doesn't work it will probably break the spring.
That is not a fatal condition. Replacement springs are available from several sources. Dixie used to have them. Not necessarily CVA but will fit and work.
As I recall, those kits sold for $39.95 in the early 1970s.

 

[George]

check the screw that holds the lock. if silver on the end its to long and slows the lock. grind off the end a bit to shorten.

voice of experience on that issue!

My experience, too, and shortening the bolt completely solved the problem.

Spence

 

[shermo]

Thanks for all these fine replies, folks!

I tried a couple different nipples. No luck. Tried smoothing down the mating surfaces behind the lock works, and stoning a bit. No help. Shortened the screw. No help. Tried pulling back the hammer to fullest extent before letting fall. No help. Did a little cleanup work on the lock inletting. No help.

So I guess I will have to mess with the mainspring. BTW, that was always my first choice, but I tried all the others first because I don't know how to take out this mainspring safely. Can you please describe the procedure? Then I will try the "leather piece" thing first, and get a replacement spring (or try stretching the current one) if nothing else works.

Thanks guys. This is a VERY helpful forum!

Shermo

 

[necchi]

They make a tool for springs called a Spring Vise, but in this case it's might not be worth getting one, so,,

Go out to the shop and get your ViseGrip.
Let the hammer all the way down too relax the spring as much as possible.

Open the ViseGrip with the adjustment bolt so the jaws are open when the lock handle is closed.

Now put the jaws of the ViseGrip about a 1/3 of the way up from the V of the spring and turn the adjustment screw in until the jaws just touch both sides of the spring.
Open the lock lever and turn the adjustment in about a 1/2 turn and close the lock lever.

The idea is to compress the spring only enough to pull it straight out.
If you compress it too much she'll snap, it'll break.

 

[shermo]

Uh-oh! This does not apply in my case -- my lock has a COIL spring. Any ideas as to taking out or fixing this kind of mainspring?

Shermo

 

[Rifleman1776]

my lock has a COIL spring

Are you sure this is a CVA???
My old brain is gettin' fuzzy but I don't recall that coils were used by anyone at that time except TC. And, I don't recall TC makin' a derringer.
The plot thickens.... :idunno:

 

[shermo]

Well, that's an interesting question. I have a very distinct memory of the box it came in, and that it was marked CVA. But how well can I trust a memory 40 years old? The barrel is marked with a serial number and the word "Spain", and nothing more. The lock says "Derringer Philadelphia", which is standard for the replicas and tells us nothing. The bore is about .45 caliber, and is rifled (I never understood why a deringer needed rifling: its effective range is about 5 feet). And the spring is very definitely a coil spring. If I can figure out how, I will try to send a picture of the inside of the lock.

Shermo

 

[Zonie]

Yup.

I know my Philadelphia Derringer is a CVA and it is marked like shermo's pistol.

It also has a coil mainspring in its lock.

It's mainspring isn't a weak little wimpy spring either. It's a pretty stout one.

To make matters worse, there is a curved metal pin that is running down the interior of the spring and this is held at the rear by passing thru a hole in a pin that is pressed into the lockplate. IMO, this pin should not be removed.

In order to get this spring out of the lock, locking pliers with a special forked nose on one jaw and a jaw with a circular pocket in it would be needed. The pocket would catch on the locks pin while the forked jaw would catch the front coil of the mainspring.

I do notice that the pocket in the nose of the hammer on my pistol is rapidly approaching the rear of the nipples cone as it falls.

If your pistol is doing the same thing, it is possible that the rear of the hammers nose pocket is hitting the rear of the cap on the nipple just at the moment of impact. That would result in the energy of the hammer being spent to pinch the copper lip on the cap rather than crushing the priming compound on the top of the nipple.

If this was happening on my pistol I would file away the rear of the hammers pocket so there could be no way that it would pinch the cap in that manner.

I suppose you could call Deer Creek and see if they have a replacement lock but when the value of the pistol is weighed against the cost of a replacement lock it might not be worth it.

 

[necchi]

Wow,
Please disregard all previous advice, as I've never seen one like that in my life! :haha:

Next time I find someone with said CVA Philly Deringer I'll have to ask if I can take it apart.

 

[shermo]

Thanks for that suggestion. I think the spring Ought To Be plenty strong enough, and the loud CLUNK when hammer hits nipple is reassuring, but.... no bang.

But I do see, now that you mention it, that the hammer is hitting the cone at a slight angle, which MIGHT be enough to "pinch the corner of the cap". I will try to fix this. But I don't want to start by modifying the hammer (I only have the one). Instead, I'll try filing the cone to change the angle at which it meets the flat of the hammer. At least, if that fails, a new nipple is easy to get.

Thanks again for this suggestion. Nothing else has worked.

Shermo

 

[Rifleman1776]

I know my Philadelphia Derringer is a CVA and it is marked like shermo's pistol.

It also has a coil mainspring in its lock.

In hand is better than fuzzy memory. :redface: