If you're saying that the hammer goes all the way down when you have the trigger depressed, that, of course, is bad news. This could be something as bad as incorrect geometry on sear/hammer juncture, or something as simple as not enough overtravel on the trigger. There are several different scenarios where this could occur. I think the first thing I would look for would be sear spring tension to insure that the disconnector is being pushed up/out. Of course, please make sure that a qualified person takes a look at it.
