There a few companys seling spring and unfinished parts for the 1877 revolver(do a google search on colt 1877 parts) finding a gunsmith to work on one will be hard as they can be tricky to get right,if the timing is out check cyilinder end movment if well worn this can be fixed with a shim,as mentioned springs breaking is the most oftern cause of trouble,the triger return spring has to be exactly shaped as the originalor you will have trouble,I oftern pick these up very cheap because somone took one apart and put it back together wrong(springs positioned wrong)just striped oiled and replaced springs properly and doubled my money,now I am starting to collect them and am kicking my self for the very good ones I sold