Be certain when you get your Timney trigger that you get one with a "high" sear. They tend to list only a single trigger in places like Midway, but there are two models. You get the wrong one and the sear is not high enough to engace the firing pin.
Some dumb ass gunsmiths will replace the firing pin with a 1903 version made for the 1903 rimfire. That will result in your trigger being able to engage the sear, but that firing pin is too short to project through the bolt face.
I had two 03s (one a 1903 and the other a 1903/A4) where the original gunsmith went with changing out the firing pins, and my second gunsmith had a hell of a time figuring out the problem and getting parts from Timney to fix the trigger.
The alternative was to grind away the bottom part of the rear end of the receivers to get the trigger sears so they would engage. I elected to not take that route, but waited forever for the parts to be shipped by Timney.
Barstooler