This is one of those times when you need a gunsmith.
better to have a gunsmith assemble it so nothing is broke
Smith and Wesson Model No. 2
Best left to a gunsmith
You need a gunsmith
Best to let a gunsmith do this.
Depends on the model
Recommend you ask a gunsmith for assistance.
Best advice is to ask a gunsmith.
Take it to a gunsmith.
Let a gunsmith do it.
You can get a manual from S&W on their website for free.
You can get a manual for free at the S&W website.