key no longer starts car

[Flash]

Its not a problem of a battery or sensor or anything. A car ive been driving required you to push the key IN hard which is not normal, it got to the point where it was needing to pushed in really hard, and now it does nothing.
What exactly needs to be replaced? Im guessing its the ignition switch? Ive never taken apart the tumbler insert but would assume its not the problem.
Its an eta if that matters.

[bmw325csi]

ignition needs a replacing, get a new key while your at it

[redsubdivisions]

Tumbler. Happened quite a bit to a number of W140 Benz's at the last shop I worked at. Might as well get a new set of keys while you're at it (or get the new cylinder lock coded to your old key if it seems to be fine).

[Flash]

thanks guys, parts are on the way, ordered a new tumbler and key set.