RougeLeader,
The titanium firing pin's lower mass means it slams into the primer with less inertia. This can fail to indent the primer fully. A titanium striker in a rifle can work because the mainspring accelerates it more rapidly than a steel one, allowing it to pick up more energy. But in the 1911 the hammer mass limits how much speed the strike can have and thereby, how much faster the lighter pin can go, and often it is not enough. I wound up abandoning one of these titanium pins myself. I bought it when they first came out, thinking to shorten lock time, but it turns out you have to go to a stiffer mainspring and a lighter hammer to have a chance at getting enough speed into it, and that messes with your trigger work. Just more trouble than its worth.
Seating long enough that the cartridge headspaces on the bullet and its head is flush with the barrel hood normally improves lead bullet accuracy and reduces leading by getting the bullet centered in the throat. If your leading is worsening with the bullet seated that way, I am a little suspicious of the barrel's throat geometry, but would need to look at it to know. A common target shooting gunsmithing practice was to apply a throating reamer to a 1911 barrel to make the taper of the leade more gradual and move it all slightly forward to make a tiny freebore for the LSWC bullet shoulders. It might be something to consider having done.
It occurs to me that if you headspace on the bullet AND you have a titanium firing pin, the pin pushing the bullet into the throat could cost it some of its energy. I've not had the problem with a steel pin and that seating method (third from left, below), but I always use Federal 150 or 150M primers, known for the sensitivity and commonly recommended for people having trouble getting the weakened strikes from a tuned revolver to fire consistently. So you might experiment with that change.
Another factor is that proper primer seating takes more force than many suspect, so you could also be failing to properly set the bridge thickness (the thickness of priming mix between the tip of the anvil and the inside bottom of the primer cup). The primer should be seated to reconsolidate the primer assembly (push the cup and anvil closer together against priming mix and foil) about 0.003" deeper than the point at which the anvil feet first touch the floor of the primer pocket.
