Yea I found the missile launcher to be too AP intensive to be a viable option since one round typically won't be enough. The Hell-Hammer lasconnon might work but again they're super AP intensive but you have a better chance at one shotting turrets. Personally, for early game tactics, I like to run a chump with a flamer close enough that next turn they'll have 2 squirts worth at it cuz turrets take 4x damage and flamers ignore armor. Alternatively, you could load half or more of your squad with Godwyn heavybolters and flight suits and spam away.