I def agree with the aim small, miss small theory. If you want to see how you would do on a deer i would suggest a 3D deer target. Then you will be able to see how you would do on a deer. If a 3D target is too pricey for you (a good one is over $120 usually) you could try what I do, get one of those five dollar cardboard cut outs of a deer and shoot at that. they usually have the vitals marked and they are smaller then most real deer so if you are getting good groups on the cardboard you will have a little more room for error on an actually deer. Other then that keep practicing and stress good form.