My favorite trick is to go to caustic caverns or tundra express and try to get the varkids to pod then kill the pods, u get a lot more xp killing the pods than u do if u let them level up. U can also go kill the warrior then after he is dead kill the rakks then look for their respawn point they will always spawn in the same spot so it is unlimited xp. If you have a buddy to run around and get u ammo while u shoot or visa versa it is very effective albeit boring and exploiting the game.
U u have an appropriate bee you should be fine. If you have never killed him before it might take some attempts to get his patterns down but if you can keep the crystalics at bay he is fairly easy to kill.
It will make each shot 2 or 3 times more powerful if its scales with my level 50 stuff but u probably will need to use a few different weapons to effectively kill the warrior, as well as the other adversaries you encounter leading up to the final fight.