Yeah- it's fairly unlikely, especially on Pro, that you'll have enough money to upgrade the BB to 50 firepower on your first playthrough. The Killer7 may well be better on your first playthrough- sell the BB at the first merchant in Chapter 5-1 and buy the Killer7 instead. It is 77000ptsas though, so it's very expensive. The BB has far better replay value, once you've got the money to upgrade it to 50 firepower, but as I said, you probably won't be able to do this until your second playthrough. The BB is absolutely invaluable for defeating certain enemies in Chapter 4- things like the Armaduras, the Dr Salvadors, the Dos Gigante and most of all, Salazar himself.