u/Correct-Most-9892

So I've been trying to get mostly high class firearms to use for the remainder of the game but noticed something inconsistent. The orange burst rifles do significantly less than the purple single shot rifle, and the orange gun does half than a green pistol fully upgraded and the same mod. I noticed when I found an orange revolver at lv.58 and another at 60 but the 58 one does slightly more than the 60. Does anyone else notice this with the firearms only or is it just me?