Help with Percussion Lock Function

[Malachi Leviticus Blue]

I picked up an older "MARKWELL" percussion pistol and am trying to figure out the lock mechanism.

If I yank on the trigger it pretends to function fine, but if I squeeze the trigger the sear catches on the half cocked position. There is no fly to hold out the sear so I can't see how it is supposed to function correctly. I've had the entire lock apart and all parts move freely. It seems to me that the half cock notch sticks out too far for the sear to clear it without a fly.

Anyone have any experience with this type of lock? What am I missing here?

I'm wondering if I'm just missing a fly?

 

[mec]

a problem for sure. It could be an excessively reduced full-cock notch. Something similar happens with single action revolver when somebody has reduced the full cock notch too far in search of a "hair" trigger. When it's done with a double action, the trigger tends to kick forward as the hammer drops causing the hammer to ease down on the safety block.

 

[4v50 Gary]

If it falls on half-cock, the geometry of the lock is wrong. Build up a weld on the tumbler right behind where the first sear notch is. Then filed it smooth. I had to do that to a Brown Bess replica.

BTW, I have a Markwell Arms rifle. I silver soldered a rib on it to make it a half stock. Unfortunately, the photos died with the smart phone.

 

[Malachi Leviticus Blue]

Well thanks for the insight guys, I was hesitant to add or take away anything from the tumbler until I at least asked around a bit.

It does have a pretty light trigger and I already thought I might want to stiffen it up just a bit.

 

[Jim K]

Normally, when the finger pulls the trigger and it releases the sear, the finger doesn't (can't) stop and pulls the sear out past the half cock notch. But if the sear has little engagement and is too easy to pull, a fly may be needed.
But that is not the case here. That tumbler has been worked on to recut the full cock notch. So the full cock notch is now deeper than the half cock notch, and the half-cock notch is catching on the sear. You will probably have to have the tumbler built up by welding and the recut both notches. That kind of work is tricky and not too many people are good at it. I have seen several hammers and tumblers completely ruined by gunsmiths trying to build them up, so I can only caution about who can do that work.

It might be easier to have someone familiar with those locks make a new tumbler; they are not especially hard to make and once hardened should work for many years.

Jim

 

[Jim K]

I did some research and it looks like that Markwell is a Spanish made repro. Based on my experience with that general type of gun, I think you may well fix one thing and find something else going wrong. My suggestion is to use that gun as a wall hanger, or trading material, to buy a better quality percussion pistol.

Jim

 

[rcmodel]

Looks to me like there is way plenty of half cock notch still hanging down in the way.

Might be able to thin it down enough to clear and still have plenty left for safety.

rc

 

[Malachi Leviticus Blue]

Jim K, from handling it first hand I can tell you that you are absolutely right as far as the full cock notch being deeper than the half cock notch. I've never had much trouble with a lock so I've never really dug in to how exactly everything works, but I didn't think that was quite right.

RC, I've been thinking along the same lines of thinning down the material at the half cock. I'd make a tracing first, in case I need to make a new tumbler.

I just need to decide if I want to add material or take it away

I'm a bit disappointed because I thought it was a functional pistol, but I always learn a lot more by taking something that is broken and making it work than I do using stuff that just works.
One of these days I need to build a complete lock anyway, just to say I did.

Thanks for the advice

 

[RaceM]

+1 to RC. I did exactly that with a Markwell kit I was gifted with.

 

[4v50 Gary]

It's fixable. Its whether you want to put in the effort.

 

[rcmodel]

Color the hammer notches on the bottom with a black marking pin, the carefully drop it past the sear with no pressure on the trigger a couple of times.

Where the marker ink rubs off is what you need to carefully file off.
Keep coloring, testing, and filing until it stops doing what it's doing.

As long as there is a working half-cock notch left, you are back in business.

rc

 

[Malachi Leviticus Blue]

Well folks I'm intent on having a functioning pistola.
Sometimes I feel like an old lady taking in stray cats!
I just cant stand to see them die.

 

[BCRider]

I've got the same issue with a poorly designed and poorly made Armi Sport flinter. In your case at least there's a bridal plate which is providing better support to the lockwork. My Armi Sport doesn't even have THAT.

Another option instead of building up some weld would be to cut a little notch and silver solder in a small piece of HSS stock cut from the shank of a proper HSS drill bit. You need to harden the shank because the shanks are left soft so they can grip the chuck jaws when used as a drill.

Because HSS needs to get up near white hot before it becomes hard you'll need to harden the drill bit before you slice off the little chunk you want. It's easier to hold when it's all one piece.

And no need to dunk it either. HSS is an air hardening steel so once it's up around white hot just wave it around in the air until it's not glowing. Then you can dunk it in some water without any fear of cracking.

Once hardened polish it clean with emery paper and use a Dremel cutoff disc to slice off a piece that's as thick as the tumbler Using a small round file make a notch for the insert to solder into. And leave the not so the outer edge is sticking well out so you have material to work with. Once it's silver soldered in place you can use the Dremel and honing stones to shape the hook depth and angle and dress the lip inward so it's still out a few thou farther from the half cock lip. That way once the sear releases there's no way for it to touch the half cock notch.

The HSS insert will be more than tough enough and hard enough that you'll never see any wear on it.

The reason to use HSS instead of O-1 drill rod or similar is that the HSS won't be softened at all by bringing it up to the dull red needed for silver soldering. If you used O-1 rod it would be dead soft once silver soldered into place.

This sort of repair is what I'm planning for that Armi Sport lock provided I can changes things around well enough to fit it with a bridal plate. It's that or I'm thinking of using the barrel to make a percussion under hammer rifle.

 

[Jim K]

It should go without saying that any fix to that tumbler or sear will require that the part be hardened. Most Spanish lock parts (in my experience) are thinly case hardened and the hardening is easily cut through. If the part is not (re) hardened, it will only wear and the trigger/sear engagement will fail again. Plus, those parts are made of low carbon steel and just heating and dunking won't harden them. You will need something like Casenit (which Brownells now sells as "Brownells hardening compound" or something like that).

Obviously welding hard (or hardenable) steel onto the parts, or making new parts out of better steel will work, but that approach can get real expensive very quickly if one has a gunsmith do the work, and probably would cost a lot more than the gun is worth.

Jim

 

[AJumbo]

I've done this surgery myself, and it looks to me like there's plenty of room to reduce that half-cock notch, but the part will most likely need to be case-hardened after the work is done. I agree with Jim K that most Euro lock parts are hardened just deeply enough to be serviceable; once you're through the hardening, you'll be amazed how quickly you can remove steel, so go slowly.

I have always wondered if a diamond file would handle case hardening.....let us know, will ya?