For anyone struggling to get a good bar muscle up or if you want to beef up on your technique

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Bar muscle ups from a dead hang are easier if you use a false grip. Kipping pullups all the way to support don't need a false grip because of its rotation around the wrist which will pop it up pretty much automatically if you are pulling down.
On a wall, you don't need a false grip because your wrists can already rotate to the position and be on top of the wall to support you. On a bar, your wrists are below the bar when you start. By taking a false grip, it partially gets your wrists up so that you only have to partially rotate them (one less thing to worry about). The transition is relatively "complex" -- right when you hit the transition when you power up with a pullup, you have to simultaneously:
1. lean forward over the body
2. pull your elbows from in front of you to your armpits
3. rotate your wrists on top of the bar to support you
It is very much similar to a muscle up on rings. The wrist problem is common. It is one of tne of the many problems I see with people trying to learn kips in gymnastics is that they fail to rotate their wrists in kips, which makes them fall off of the high bar/uneven bars backwards. They won't be able to support themselves because their center of gravity is put behind the bar if the wrists are not on top.