Timmey, pretty expensive but a good trigger, Rifle Basix makes on also never had one on a ruger but have one on a Marlin 22mag it works good also,

DONT file or grind your safety , do the work to the new timney trigger it has paint on it where your supposed to do the work. If you feel CONFIDENT with a file or dremmel this works great but you only have one shot at it and I cant stress enouph that you need to be compentent to do this!!
http://i56.photobucket.com/albums/g184/Morgan5_2006/triggerforweb.gif