could just be dirty. try removing the firing pins and cleaning the pins and bores very carefully. you may also want to polish your firing pins so they slide more easily in their bores. with these guns as time goes on and the hammer faces get a little worn where they strike the pins you can get light hits. another thing to consider is the hammer springs themselves could be a little tired. im pretty sure you can find a source for heavier hammer springs as well. Hope this helps.
Jimmy has the hot part no for the lower firing pin. Also, use the Wolff Extra power mainspring, no.30217. Use this spring for the right, or lower hammer. Save the other one, they come in packs of two, for a later service.
Make sure the firing pin channel is clean and free of burrs.
sakoboomer - you need a gunsmith - if you haven't taken the buttstock off or haven't looked at a schematic of your gun you really need to take it to someone who understands how the gun works. I will tell you the gun should not do this.
Give it to a competent smith.. my older XT mis fired on occassion. My smithy took the gun from me after he noticed a mis fire. Disappeared with it in his trailer for 20 minutes and whatever he did worked.. The gun hasn't missed a beat since. It'll fire anything I put in there.... even mis fired shells from a Perazzi....