Here is a simple but very effective way of eliminating that nasty trigger over-travel. This great little tip was given me by David Lake of Composite Gunsmithing and Custom CARBON FIBER and KEVLAR stocks and pistol grips; http://compositeguns.com . I have found David to be both knowledgable and eager to help with advise based on experience.
Although this can be done to any trigger that has no over-travel adjustment, below is detailed the procedure used for making an adjustable over-travel on a Ruger 10/22 rifle.
The trigger was removed from its assembly and a hole was simply drilled and tapped through the trigger so that a 6 X 32 set screw could be screwed through it. The hole was drilled so that the screw resides just above the trigger spring and at a like angle as the spring. This position places the screw as far out of sight as possible and drives the screw directly onto the inside face of trigger guard when the trigger is depressed.
The set screw was fashioned by cutting the head off a 1/2 inch 6 X 32 hex screw and cutting a screw driver slot in its place. It was then shortened so that it would not protrude from the trigger face when adjusted. The screw was then re-blued using a good cold blue solution.
After field testing to determine the optimum adjustment (zero over-travel without interfering with trigger pull) the screw will be locked in place with a thread lock; a drop of super glue, finger nail polish or the like on the back side of trigger.
Left - The hammer strut and spring assembly (B18, B44, B45) is pulled out after un-cocking the hammer. Center - The hammer pivot pin (B19) is pushed out. Right - The hammer (B17), hammer bushings 2 (B43), and bolt lock spring (B42) are removed.
Left - The trigger pivot pin (B21) is pushed out. Right - The trigger/disconnector/disconnector pivot pin assembly (B20, B25, KE-28), sear (B23) and sear spring (B24) are removed by pushing trigger through the top of trigger guard (B2).
Left - The disconnector (B25) is pivoted so that the sear (B23) (sear spring hole facing up) lays below disconnector. The sear spring (B24) is then inserted in the spring holes on disconnector and sear. Right - To keep the assembly together while installing into trigger guard (B2), a round toothpick is inserted through trigger pivot pin hole and cut flush with trigger. The assembly is then put in place through the top of trigger guard. The trigger pivot pin (B21) is pushed through trigger guard and trigger with the temporary toothpick pin being pushed out the other side of trigger guard by the pivot pin.
Left - The bottom arm of bolt lock spring (B42) (forward of bend in spring) lays in a small dimple on the top of bolt lock (B41). Center and Right - The four hammer components (hammer, hammer bushings 2 , and bolt lock spring (B17, B43, B42)) are held in place and inserted into trigger guard (B2). The bolt lock spring is first placed on bolt lock (B41) as shown (above left). Then the assembly is slowly pulled backward until there is enough clearance to slip upper arm of spring under the magazine latch pivot & ejector pin (B35) as shown (above right). The hammer pivot pin (B19) is inserted through the trigger guard and hammer assembly.