Its illegal here so you may want to check up on it in your area, but yeah it would kill a deer. Its all about shot placement and knowing your distance. A deer shot in the vitals with a .410 is just as dead as one shot with a 12 gauge. I use a 12 gauge myself because you've got more power and you don't have to make a "perfect shot" If you worry about the kick of the gun your using though you wont be accurate and accuracy is way more imporant than power.