Any regular AR trigger will work in your Ruger. What won't work is any trigger labeled "large pin", which are only for older Colts manufactured during a specific time period. Since large-pin Colts are a small minority in the AR world, those triggers will always be specified. Geissele specifies which triggers are large pin. The regular SSA is not, but they do make a special large-pin version of the SSA.
Basically, what I'm trying to say is that unless it's specifically labeled "large pin", any AR trigger will work in your Ruger.
