Welcome to the forum.
You have a 2nd Model LARGE FRAME HAMMERLESS (smokeless powder capable) 5th Variation (circa 1916-1924.) The serial number is fairly high in the observed range so production of your piece is most likely late in the time period, 1922-23?
"Standard" offering for this model: 3 1/4" barrel; Nickel finish; molded, black hard rubber; caliber offerings: 6x.32 S&W Long or 5x.38 S&W (not .38 SPECIAL). Options offered: 4, 5 or 6 in barrels; blued finish (becomes more common in later production); checkered walnut or Mother-of-Pearl grip panels.
Looking at the Numrich/GPC site, they have a schematic available (under NEW MODEL LARGE FRAME HAMMERLESS) :
- but show the original trigger return spring as out of stock. Other folks have had problems with fitting the "non-original replacement" spring - is that one that you have tried.
You might try:
they seem to have a fairly good supply of parts. Good luck.