It all depends on how well you understand the gun of course. I have filed and stoned many to perfection and it is not difficult. Maintaining the geometry and (assuming a New Model gun) reducing the hammer notch engagement to .020" or so will leave you with a pretty fine trigger. I do not play with springs, generally. If you lose perpendicularity at the sear engagement surface on the hammer you could end up with an unsafe trigger. Fortunately, the hammers are only $30 if you blow it so it's not a big deal and then you will have learned. At least that's how it was for me.