Pietta 1860 Army? Nice guns. I've fixed a few. Some new in the box were brought to me to "tune".
First thing to do with a Pietta is to loosen the trigger bolt spring screw a full turn. The cylinders are soft as all the Italian cap&ballers seem to be. The bolt will begin to scar the cylinder the first time the hammer is drawn back.
I like to weaken the spring on the bolt leg of it so the cylinder has a chance at looking new fer awhile. Hate the damaged cylinder from the hard bolt head hitting it. Those wire replacement springs by Hiene and others are good to use. Brownells gunsmithing supply sells them as others do too. I think Wolf Springs sell them too. Hardware stores usually sell the piano wire that can be bent into a trigger bolt spring. I've gone that route before. I like to stone the bolt leg on the trigger bolt spring and just adjust the "hit" of the spring to be lighter so it can't damage the cylinder and it's notches. Loosening the screw that holds the trigger bolt spring in will be a temporary fix so the action can be worked but not everyone will want the trigger lightened also as happens when the trigger bolt spring screw is loosened.
That said there is another thing to do first off before working the action of a Pietta.The bolts seem to always be in the cylinder notch when the hand tries to turn the cylinder so the bolt head broaches metal from the off side of the notch edge. That's the edge that does the stopping of the cylinder when it hits the bolt head. Don't need it minimized any at all by the bolt head removing metal from the edge of it.
The remedy is to make the bolt head get out of the notch of the cylinder before the hand on the hammer turns the cylinder. That means the bolts leg that rides the hammers cam needs to get closer to the hammer cam so the bolt can work in the timing of the action before the hand turns the cylinder.
Doing that with the bolt means taking it out of the gun and filing with a diamond file to the under side of it(under side when looking at the gun upside down with the trigger guard off the gun0. Filing there puts the bolt head further up in the bolt window in the frame and the head needs filed down to put it back to specs and have it go to the bottom of the cylinder notch when it's under side is on the frame. The idea is to file the under side of the bolt on the bolt head side of the bolt screw so the leg on the other side of the bolts screw gets closer to the hammer cam. Like a teeter-totter the bolt moves on it's screw. One side goes up and the other goes down. So if the bolt head goes further down in the frame window(the guns upside down) the other side where the bolt legs are goes up and closer to the hammer cam making the bolt move sooner in the timing of the action. That gets the bolt out of the cylinder notch before the hand turns the cylinder.
Next thing......shorten the bolts leg that rides the cam so the bolt gets off the cam and the whole width of the bolt head gets back to the surface of the cylinder "before" the edge of the cylinder notch. There will be a small amount of space between the bolt head edge and the edge of the cylinder notch. The timimg of the Pietta seems to always have the bolt head hit partly on the edge of the cylinder notches which causes the hard bolt to peen down the edge causing problems with the bolt being able to "get in the cylinder notch" to lock the gun in battery. The bolt will damage the edge of the cylinder notch from hitting it when it snaps back to the cylinder. Don't need a damaged cylinder on a new gun. The damage will happen relatively quick so don't work the action more than needs to be done to asertain the timing is off as explained here. Make sure the trigger bolt spring screw has been loosened a full turn before working the action to examine the timing. Put a small dab of grease in the cylinder notch ramp(lead) before the notch. That can show the bolt is hitting on or too close to the edge of the cylinder notch.
Try to be objective about what I say since I've "fixed" more than a few of these cap&ballers. Things will be as I say unless there have been changes to the Pietta's factory timing I don't know about. Haven't looked at any new ones lately.
