How do I increase the max number of frames? I'm currently working on a project that has a total of 304,593 frames, but when I fed this number into the timeline end point it reverted back to a solid 300,000. This is a hard limit for those wondering.

I cannot input more than this many frames, is there a way to override this? Including possible python options.
This limit cannot be changed. You cannot alter builtin properties deriving from bpy.types.Property. Every attribute in api docs is marked as readonly.
The scene's frame_end property hard and soft maximum is just set to 500,000*.

If you need to render longer video than that you will have to do that in another software.

Using negative frames or messing with time-remapping does not help.



*As of 2nd March 2016 the maximum is 500,000 (previously 300,000):
https://developer.blender.org/rBf7062b2407c65dcf85904242281a13339d47a20a