Killing Range for 12 vs 20 gauge???

[Big joe]

I've shot many a jack rabbit with my 12 ga. Mostly in 6-8 shot loads. I have yet to realy tell how far away I can humanely take a shot at one in the Utah sage brush. Also I have recently bought a 20 ga for my son so I have the same question for his 20 ga.

So can you tell me the effective killing range for jack rabbit sized animals with these two guns???


Thanks for your input!!!