I don't really get the 1 bb/1 bullet thing.
For one, as preciously said, shoot better/heavier BBs.
Apart from that, whether you're carrying 300 BBs in one hicap and 10 real caps doesn't change how many BBs you have on you. Even if its taking you 10 BBs/kill that's 30 kills before you need to go reload FFS. Don't be a munchkin.