Everyone should read through this page: http://teamfortress.tv/thread/18376/major-tf2-update-for-6-18-14-6-19-14-love--war/?page=1

In particular:

- All mini-guns now have damage and accuracy ramp up after they start firing. Full accuracy and damage is reached 1 second after firing.

- All Demoman stickybombs now have damage ramp up. Full damage is reached 2 seconds after firing.

- Sentry bullets are now affected by damage falloff outside of sentry scan range