How familiar are you with the lockwork/innards of a S&W? My first reaction is to ask you to find a local gunsmith, there might be a number of things going wrong that need to be fixed. If you are determined to fix it yourself get a copy of Jerry Kuhnhausen's S&W Shop Manual to start with. I don't mean to sound condenscending, but the book will really help - I'm speaking from hard learned experience (I've managed to mangle a Smith or two).
Cyclinder fore and aft play is usually called endshake and can be fixed with bearings(shims) available from Brownells or, the "more proper way", is to have the yoke barrel stretched by a competent gunsmith. The cyclinder stop may need replacing along with the spring that tensions it, and the hand and rebound spring come to mind. There could be other issues that need fixing, but those are what I'd look at first.
1917 are great guns and your revolver is fixable, it might be easier fixed by a smith though.
What will5a1 said. The only thing I'd add is that you'd be wise to choose a professional 'smith with a real bricks-and-mortar business and a reputation for doing quality work instead of some 'friend of a friend' you hear of who works cheap out of his garage.
Don't ask how I learned; it's still painful and hard on my blood pressure to recall in detail.
Believe me, any extra money is well-spent and nothing compared to what it costs to repair or replace a ruined revolver!
You might want to start out checking with the American Pistolsmith's Guild site for shops in your area.