I load up in this order:
1) bean bag - just to put the guy down and not kill
2) 9 shot - hopefully won't hit or stray into other room but put someone down
3) 7.5 shot - a little stronger
4) 4 shot - another step up
5) 00 shot - show stopper
6) slug - for some reason need to shoot more, must be some good reason, went to slugs
7) Brenneke K.O. sabot - not messing around now
8) Brenneke K.O. sabot - ditto
9) specialty slug (go through everything, disable getaway car, lol)
If you are using all 9 rounds, something is going wrong, overwhelmed, or Zombie invasion.
Other shotgun has 8 rounds.
Placed a shootgun in safes on two main floors.