I believe the OP's intention is to bring a more realistic feel to the projectiles.
If the concern is that targets can quite easily dodge the BBs at low speed, I would suggest the use of black BBs. I believe it would be harder for the target to see the BBs coming even at low speed, thus, making it harder to identify the position of the shooter. If you are in a milsim mindset, I guess you wouldn't mind not having the "tracing" effect of white BBs.
If the concern is engagement distance, than I guess the only solution for more "hardcore" milsim rules is to allow for greater musle energy of the primary weapon... these kind of games should be reserved to players who know what they're doing, are aware of their minimum engagement distance and lower musle energy side arms should be mandatory.
This is if there's no better technical solution to keep a straight path and reduce drag of the BB.