Help: Key Ignition is VERY hard to turn

Replaced the tumbler and turning mechanism on my BMW to match a new key I had made back in March (four months ago).

Problem: Very stiff to turn once the key is inserted. It's been like this ever since I reinstalled it. Requires a bit more force and precision to get it to "click" and allow me to engage the ignition. Sometimes, it takes me 4-5 fails before I can hit the sweet spot.

Not smooth to turn like she once was. I have even put this lubricant specifically designed for locks, keys and tumblers. Helps very slightly with inserting the key, but doesn't make turning it to ignite the engine any easier. It's not really an oil problem so much as it is the amount of precision and sometimes even force to start the car. Because sometimes it works instantly, sometimes it won't budge.

Thoughts?