Re: Switching an ADL to BDL
Correct, the actions are the same.
To make the conversion, you'll need a different magazine box. The ADLs I've done this on had a slightly taller box so the floor plate won't quite match up to the stock, and of course you need the floorplate/trigger guard assembly. The follower is the same, or at least I've been able to use ADL followers in the BDL. Usually I can use the mag spring as well.
Brownells sells parts conversion kits but these have some extra stuff I didn't need. I generally just call the Remington service department and give them parts numbers I got off their web site.
Flex is for people who don't have lockers.