Board Thread:General Discussion/@comment-5996974-20130116090312/@comment-5976647-20130116145012

I am not sure what you mean here.

What I do for weapons is specifically farm the missions that have the random boss encounters. I take the weapons I earn there and upgrade the weapons I have that match the guys I have. For example, I will farm the Optimus Prime random encounter over and over and then feed his weapon to my Slipstream upgrades.

As far as I know, upgrading a weapon with the same weapon will make no difference. Of course, I have not tested this so I could be wrong.