On a scale of 1-5, one being the lowest and five the highest they rate a 3. Taipan's are a 5 and Copperheads are a 1. So how exactly is 3 not potent? The LD50 for B.n. is 0.02 of an oz for a 150lb man. And that LD50 of 8.6mg per kg is intra-muscular. Intra-venous it's much higher for the B.n. than the B.g.; 1.1mg/kg vs. 6.7mg/kg respectively. Also those LD50 scores are based on MICE not humans. Monkeys are far more sensitive to B.n/B.g venom than mice are. I am pretty sure we are more comparative to primates than mice.
here something you can maybe grasp. LD50 for various snakes