Kirst in Pietta 1858

Lefty County · December 27, 2007, 09:45:43 PM

Hi,

This is my first post. I've seen good info here, so I figured that I would throw a question out:

Has anyone else had problems with Kirst cylinders jamming when the hammer is dropped from full cock to half cock on the two short "cylinders"?

From what I can tell, the hammer is coming far enough forward that the hand is slipping down to the next ratchet on those two cylinders. I have replaced both the trigger and hammer, as well as trying two different length hands. I have modified a hammer to move half cock lower, so for most cases I can at least drop the hammer, but that still has an issue on one of the cylinders.

The Pietta is 2007 production/proof marked. The Kirst cylinder is gated, 45LC. The original hammer's half and full cock notches are in the same locations as my Uberti, so I think that is normal.

Timing is perfect with the percussion cylinder, and the revolver is very smooth with the kirst, other than being able to make it jam.

At this point the only that I can see left to try is to modify the ratchet on the cylinder itself.

Thanks in advance!

County

Oldelm · December 27, 2007, 10:15:54 PM

Howdy lefty,

Welcome to the forum.

I'll try and respond to your question, but I don't think I know what you mean by the two short "cylinders".

Anyway, I don't generally go from fullcock back to halfcock, cause I've noticed it's easy to get jammed, ..and I try to cycle the action on these single action guns as smoothly as possible , so as not to mis-cycle and in a moment, score the cylinder by having the bolt come up while the cylinder is misaligned. If at fullcock, and want to go to halfcock,...I'll ease the hammer down below half cock while holding the trigger back,..till I hear the clicks of the bolt leg falling off the hammer cam,..then ease off the trigger and gently pull the hammer back to halfcock. Do you follow?

I wouldn't try to modify the ratchet on the cylinder,.
I'm sure other folks here might be able to help you more.

Pettifogger · December 27, 2007, 10:17:22 PM

A lot of Ruger Old Armies do the same thing. Try this as an experiment. Take the stock trigger and hammer and take a little short piece of brass rod that will just fit in the bottom of the half-cock notch. (In other words, laying sideways in the notch.) You can take the hammer to a hobby shop and try the different diameter brass rods until you get one that fits. Glue it in with some red loctite and after it has dried, put the gun together and try it out. If it works, you can shoot it as is or you can heat the hammer and remove the rod. Then clean the slot and rod and solder it in. If it doesn't work, call Kirst. (Also, when you are talking about short cylinders and the ratchet on those two cylinders, are you talking about the chambers? I'm not 100% sure what you are talking about.)

Hoof Hearted · December 27, 2007, 10:45:34 PM

I'll chime in here also..........

If you mean chamber when you say "cylinder" how can it have "two short" ones

Now, I'm not trying to be rude or impolite. We all need to be on the same page!

I think Pettifogger is trying to show you how to let the sear on the hammer bypass the half cock notch on the hammer (by the way Pettifogger COOL solution).

If the situation is such that the only time you experience this binding is when you try to go from full cock to half cock, don't do that (kinda like it hurts when I do this, "then don't do that"). All single action designs shoud ALWAYS be cycled completely through ther action (all the way back.........all the way forward). I have experienced binding with a couple of R&D cylinders on one CHAMBER in the past but have never run into the problem as you describe it with a Kirst.

Contact Walt Kirst here: kirstkonverter@usfamily.net

He will gladly fix your problem, he's a GENT!
It's not worth your continued frustration.

Lefty County · December 28, 2007, 11:48:44 AM

Sorry about the confusion. By short "cylinders", I meant the timing between them, not the length! If you look at the spacing the throw between the safety "cylinder" and the adjacent real cylinders is very short. Those are the two I have had the issues with.

I don't normally go from full back to half cock, but I have had A (i.e. one) short stroke put me there, so I prefer to get this taken care of before trying a match with these.

Interesting thought on partially filling the half cock notch to move half cock back. Putting too much filler in there will leave a very thin part of the half cock notch retaining the sear, but it may be worth a try.

My preference would be to weld and recut the half cock, but having moved this past summer, I don't have my welding rig back up. So I basically dismissed that a priori. Moving the half cock forward helped a lot, but there is a spot where you can still get jammed after the two short throw cylinders have gone by. Made loading and unloading a easier though.

I have had too many guns messed up by "professional" smiths, or have had to fix the same for others for the same reason. So, I tend to do my own work - which I enjoy. I will contact Walt though.

County

Hoof Hearted · December 28, 2007, 04:20:34 PM

County

I'm on a much better track now............

I would first check my timing and concentrate on where and when the bolt is rising. This could be why you are having your problem.

I will go outside and do a little research if I get freed up with paperwork, then I'll get back to ya!

Lefty County · December 28, 2007, 07:40:05 PM

Hi Hoof Hearted!

This is occurring after going to full cock, then letting the hammer back down. So, the bolt is already in the up position, as it should be.

County

Hoof Hearted · December 28, 2007, 10:13:07 PM

Quote from: Lefty County on December 28, 2007, 07:40:05 PM
Hi Hoof Hearted!

This is occurring after going to full cock, then letting the hammer back down. So, the bolt is already in the up position, as it should be.

County

Sounds like you have it all figured out!

Lefty County · December 28, 2007, 11:09:14 PM

If I had it all figured out, then it wouldn't jam!

I'm thinking that with the way the Kirst is designed, the half cock notch must be moved...

County

Hoof Hearted · December 29, 2007, 09:32:22 AM

I'll try to help you again $:-\$

Walt's design is not the problem, I have half a dozen that all work fine. I have fitted dozens more and there are thousands in circulation. That being said you have a tolerance "stacking" problem on the Italian end of things. Go back to all stock (with the Konvertor installed) and make sure that the bolt is coming up (not too early and not too late) just before full cock like it's supposed to on ALL chambers. Then with the main spring removed see if the hammer is "free" to fall all the way to the firing pin after trigger release (on all chambers). I think the bolt leg that rides on the hammer cam is binding (because of tight tolerences) in your revolver. This can be exacerbated by timing issues. I recently experienced a problem close to yours and I thinned the cam side of the leg until the binding quit (after setting the bolt timing) and fixed this gents problem. Of course there could also be burrs present in the hand channel, on the cam, etcetras.

I realize it's easy to get discouraged. Buy some extra internal parts before you start.
I'm not sure where you purchased the pistol but if it is returnable, you might try another.

Lefty County · December 29, 2007, 11:51:25 AM

Quote from: Hoof Hearted on December 29, 2007, 09:32:22 AM
I'll try to help you again $:-\$

Walt's design is not the problem, I have half a dozen that all work fine. I have fitted dozens more and there are thousands in circulation. That being said you have a tolerance "stacking" problem on the Italian end of things. Go back to all stock (with the Konvertor installed) and make sure that the bolt is coming up (not too early and not too late) just before full cock like it's supposed to on ALL chambers. Then with the main spring removed see if the hammer is "free" to fall all the way to the firing pin after trigger release (on all chambers). I think the bolt leg that rides on the hammer cam is binding (because of tight tolerences) in your revolver. This can be exacerbated by timing issues. I recently experienced a problem close to yours and I thinned the cam side of the leg until the binding quit (after setting the bolt timing) and fixed this gents problem. Of course there could also be burrs present in the hand channel, on the cam, etcetras.

I realize it's easy to get discouraged. Buy some extra internal parts before you start.
I'm not sure where you purchased the pistol but if it is returnable, you might try another.

OK, so what you are saying is that you think it is the bolt leg that is preventing the hammer from being returned to full cock?

The bolt had a burr that was causing backwad rotation with the Kirst cylinders, not the percussion, which I have dealt with. That was a tolerance stacking issue.

The bolt is coming up and just barely touching the edge of the cylinder just before the slot (about 3/4 on the ledge). The snap as the leg slips the cam occurs as the bolt and notch come into line. The trigger drops into the full cock notch just a hair before the bolt snaps into the notch. I have the spares on hand, and could fit them for a later bolt rise before the snap.

Taking the hammer forward from full cock back to half cock, the bolt is staying up (as it should). The hammer is free to fall all the way to the firing pin (when the trigger is kept back), BUT will rebound about an 1/8 of an inch if the hammer spring is not in the gun. This appears to be caused by the hand spring. The amount of force required to take the hammer to the firing pin from the rebounded position is very, very little. The bolt stays up the entire time. The bolt will drop if the hammer is then pulled backward beyond the rebounded position. The hand is not yet engaging the ratchet at this time.

On the cylinders where it will lock when dropped from full to half cock, the hand is slipping down to the next lower ratchet. This can be seen with the back plate off. The hand's engagement with the ratchet, with the bolt up is what is keeping the hammer from moving back out of the hack cock position. The hand can not be any longer or the pistol will not cock on the 6th cylinder (i.e. hammer all the way back against the frame. Correction: Bolt locked, hand stops hammer against the ratchet). What little play I have left there is shorter (in terms of hand length) than the additional length required to keep the hand from slipping to the lower ratchet on the two cylinders where it will lock.

This half cock jam condition does not occur with the percussion cylinders.

Identical behavior in two pistols, with two different Kirst cylinders. Swapping the cylinders between the guns changes nothing. One thing I will say for the new Piettas is that they are consistent.

County

Lefty County · December 29, 2007, 11:53:41 AM

Forgot to mention that the cylinder to bore alignment is EXCELLENT, every chamber, both Kirsts, both pistols.

County

sundance44`s · December 29, 2007, 05:51:33 PM

One thing I`ve noticed about the Kirst and R&D drop in cylinder ..the notches for the lock up lug is made a little different ..a bigger problem in some guns than others ...it seems the notches are cut a little shallow and or a little narrow ...I`ve taken a little off the width of the lock up lug on these pistols to releive the problem instead of sending the gun and cylinder back to the company I bought the cylinders from to be fixed ..for the most part , I`ve been very pleased with both the Kirst and R&D cylinder ..they do both have their good and bad points though .

Lefty County · January 01, 2008, 06:44:16 PM

Quote from: Pettifogger on December 27, 2007, 10:17:22 PM
Take the stock trigger and hammer and take a little short piece of brass rod that will just fit in the bottom of the half-cock notch. (In other words, laying sideways in the notch.) You can take the hammer to a hobby shop and try the different diameter brass rods until you get one that fits. Glue it in with some red loctite and after it has dried, put the gun together and try it out. If it works, you can shoot it as is or you can heat the hammer and remove the rod.

This was the key. I didn't fill the notch - it took too much fill to be able to always go back to full cock on the two chambers that were causing issues. I did cut back the lip on the half cock, which was very long, and thin. Now at least I can always go to the hammer down position, and the half cock is still strong enough that you will break the trigger before the notch.

Sundance44, I guess I lucked out. The stop notch/bolt fit is basically perfect on mine. Rock solid lockup with perfect alignment.

Thanks
County