1851 Pietta bolt issues

[Sulring]

Hello, during Covid I got into revolvers, namely open top 1872 Unbertis (2 of them), and a rehabbed Uberti 1873. It had a locked action, sold as a gunsmith special. After a new hammer, trigger, spring, hand and bolt, it worked great. Recently, I saw a brass frame 1851 Pietta Colt (Cabelas stamp) with a locked action. When I get it, I start fiddling with leftover parts. The wedge locks the action hard at not quite 100% in so the wedge spring locks. But that is just the first thing I notice. I already own a Pietta in the same exact model, and I use it for comparison.
I pull all the innards, and the hammer nub for the bolt seems worn, one arm of the bolt is broken, and the trigger is worn uneven. With spare worn parts, it won't cycle right, bolt isn't engaging, and cocking takes it past TDC by about halfway to the next nipple. No matter, order all new parts.
In goes the new, and..... total manure. Hand doesn't run smooth, so polish that. When I put the bolt in, it is almost impossible to move to full cock, catching on the hammer nub/lock prior to going full. So I polish the bolt arms to make is smoother. Now it cycles to TDC.
Last but not least, it all seems to run right. Twice. After the second cycle, the bolt stays in the locked position. If I take it apart, force the exposed bolt down with a finger, it clicks and the gun will cycle one time. Then the bolt stays locked. Tried ALL the spare bolt springs I have, they all do the same. I have tried 3 bolts ( 1 used, 1 new from Taylor's, and one was a removal off a new Pietta 1851 Navy pistol.

Anyone have any clue what the ghost in the machine is? It is like playing whackamole.

 

[Ed C.]

If the bolt stays in the locked (up) position, it may be the bolt arm slipping past the cam nub on the hammer. Caused by a worn cam and/or the the bolt arms being too narrow, not tightly pressing between the hammer and frame allowing the bolt arm to slip over the cam. New parts do not always mean proper parts. I've found that ghosts are often something I assume is working, but in fact is not. Good luck!

 

[45D]

Well Sulring, action parts are oversized and need to be fitted. It sounds like the bolt isn't resetting (not engaging the cam) as well as the hand being too long.
Normally the first step in setting up the action is getting the hand length correct. In your case, the bolt arm "reset cut" needs to be adjusted so you have bolt movement. The reset cut is the crescent shaped cutout on the left bolt arm ( the left arm does all the work, the right arm lays against the frame and provides support). Open the cut to allow the cam to rest in the cut when the hammer is down. You can hear the arm reset when the hammer is almost completely down ( it's the second "click" of the two you hear when letting the hammer down, the first being the hand selecting the next ratchet tooth).
After you get bolt movement (left arm riding the cam) from rest you can start with hand length.
The hand will be the right length when you get the bolt locking the cylinder at the same instant the hammer reaches full cock. That becomes the "cycle length". After that is established, you can adjust the "bolt drop" ( left arm falling off the cam).
Bolt drop (bolt on the cylinder) should happen at minimum fully the width of the bolt before the locking notch. That is adjusted by removing material from the end of the bolt arm.

Mike

 

[CapnBallGreg]

Well Sulring, action parts are oversized and need to be fitted. It sounds like the bolt isn't resetting (not engaging the cam) as well as the hand being too long.
Normally the first step in setting up the action is getting the hand length correct. In your case, the bolt arm "reset cut" needs to be adjusted so you have bolt movement. The reset cut is the crescent shaped cutout on the left bolt arm ( the left arm does all the work, the right arm lays against the frame and provides support). Open the cut to allow the cam to rest in the cut when the hammer is down. You can hear the arm reset when the hammer is almost completely down ( it's the second "click" of the two you hear when letting the hammer down, the first being the hand selecting the next ratchet tooth).
After you get bolt movement (left arm riding the cam) from rest you can start with hand length.
The hand will be the right length when you get the bolt locking the cylinder at the same instant the hammer reaches full cock. That becomes the "cycle length". After that is established, you can adjust the "bolt drop" ( left arm falling off the cam).
Bolt drop (bolt on the cylinder) should happen at minimum fully the width of the bolt before the locking notch. That is adjusted by removing material from the end of the bolt arm.

Mike

Mike, thanks for this input. Your step by step procedure really helped me understand the action in my pistol and pinpoint my problem... the broken bolt that had been repaired but not fixed. I also took your advice about having to fit new parts. I was hoping there was a product with a better fit, but decided to fit the oversized replacement that I received. I took some grinding with a dremel tool but I got 'er done. I fired a cap OK, now looking forward to go out to the range soon and complete testing

CapnBallGreg