Not to mention the fact that a .410 slug (1/5 oz) is barely over 100 grains.
Actuaslly it's about 87 grains and I agree....it's a darn poor load for deer. I occasionally use a M-92 Winchester in .25-20 for deer and it's energy is about 700 ft-lb at the muzzle.....just because I've killed deer with it don't make it a deer rifle. Some states like mine require 900 ft-lb at 100 yards as a legal requirement.....I don't know about your state but nevertheless the 410 is still a underpowered round for deer. Do as you see fit.....