I always aim a little low. I have killed 5 deer with my bow and 4 were heart shots. 40 or 50 yds was my longest track so far.
I am going to start to aim a little lower, since my bow is no speed demon and it not that quite i think i will still get a good shot if they jump the string a little.
ABSOLUTELY!!!! My whole set-up from where I set pins to where I aim is based upon the margin of error. If I'm shooting 30 yds, I put my 32yd pin DEAD on the heart. If that deer drops a little, I'm double lungs, if he holds and don't drop, I'm just cut his aorta off. I've heart shot a few and I've cut a few aorta's off. And I've double-lunged quite a few!!! I think the big KEY is staying in the lower half of the chest cavity as that is where the vascular system is largest!!! Those "pulmonary veins and arteries get BIGGER the closer to the heart they are!!!