i went hunting this morning. it finally got cool enough, i had a doe walk across in front of me and a few minutes later this came behind her. i made a heart shot at 80yds. he jumped Stright up and kicked like they do when hit in the heart, but he loped off with his tail in the air like he wasn't hit. but you can't always go by that. there was no blood, i walked into the thick woods and found him dead about 50yds in. anyway a 40cal. do work. it broke 2 ribs going in, clipped the heart and bottom of the lungs. 60gr. of goex 3f and a round ball,,,,,,,,,,,,,,,,,,,,