turn on autolevel (x) when you go to the norden.
use autoclimb (alt+x) for your climbout, then you keep climbing when you go to a gun station.
When you return to the cockpit, the autopilot picks up in the last mode you had engaged, which sounds like you're using autoangle (shift+x)
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Air power is a thunderbolt launched from an egg shell invisibly tethered to a base. - Hoffman Nickerson