The story so far.....

 

Took delivery this PM of Perrins pinfire revolver from Holts. Considerable surface rust, but original bluing visible so may clean reasonably. Hammer free but trigger frozen. No sign of screws ever being undone, so good chance no interior buggerrup. Serial No. 2464, and I think English proof marks but will confirm after further cleaning. Currently soaking in oil prior to any attempt at unscrewing. Initial viewing looks better made than most similar Continentals. Thought it might have been a buy in for them to sell as pot boiler, but proof marks and standard of manufacture certainly suggest an above average piece of it's kind. 

Note the hammer has a rough rearsight on it, which I have not seen on Liege proofed guns. I haven't been able to sort the action problem. The lock up is caused by the cylinder hand, which jams the trigger when it engages the rear of the cylinder. Action works fine with the cylinder off, in fact works with the barrel and cylinder unscrewed four turns. Hand is free in slot, and it's spring works Ok. Pinfires are the subject of our MLA Branch meeting next month, so I shall seek advice there.

Update on the pinfire. Opinion at the Club, including from Jim Hallam, is that it was made in Belgium and imported by Perrins in the white, then finished by them and proofed. Not uncommon practice at the time. 

I know what is wrong, and I know what is needed to fix it, but I don't know how it could have gone wrong, or what stopped it working. Basically the trigger returns too far. This means the hand, or pawl, which is attached to it presents to the cylinder at the wrong angle and cannot rotate it, so jams the trigger. Also the trigger is disengaged from the hammer, so can't be pulled back with it to cock for single action (the action works fine double action with the cylinder removed and if the trigger is held back about 1/8th inch it engages with the hammer and works as single action). Thing is, nothing seems broken or bent. There is no positive stop for the trigger, it comes to rest against the rear of the slot in the frame. I can't see that there are any missing parts, though so far can't get the trigger and hand out. Conundrum, can't get trigger out because hand fouls on bottom of it's slot, and can't get hand out because it is attached to trigger. Working on it. I can make a fudge to hold the trigger back, but it would be nice to know how it was originally done.

Will let you know when I have solved it.

Finally got everything out. There is a small section in frame rear of trigger that was firmly rusted in, and I have now got out, enabling removal of trigger and hand. Pics of all innards attached. Nothing apparently bent, broken or missing. I can sort the trigger return by soft soldering a shim just below sear, but would like to know what went wrong and how. Think it may end up being one of life's eternal mysteries.

Wonder why so many were made with folding trigger. Seems a particularly useless feature to have it just flapping about.