I am looking for a smooth trigger and a shorted hammer for my M18 revolver.
Where can i find it?

/Johan

I bought a used hammer and grooved trigger from Hoosier Gun Works for $30 and did the work myself. It's not that difficult if you have a Dremel tool, some sanding drums and a few sheets of emery cloth. The whole project cost me around $55, but only because the hammer didn't come with a hammer nose or DA sear attached and I had to buy them. It took some time and elbow grease, but it also cured a timing issue I was having with the gun, so it's working better than ever now and I learned a lot in the process.
Give it a shot (no pun intended). If you hang onto the original parts you can always put them back in if it doesn't work out on the first pass. There's plenty of info and guidance here to keep you on track.

If you're meaning a "bobbed" hammer be aware that lightening the hammer on a rimfire isn't a good thing like on a centerfire. It will require more mainspring tension for ignition. Rimfires work different than centerfires