Here is my son with a Mulie in SD last fall. .223 rem with 55gr bullets. 90 yards. Deer ran 40 yards with blood squirting out.
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Believe it or not...This is the entrance. .223 Rem. Barnes 55gr TTSX, 90 yards.
Exit. Through the heart and lungs. We should have taken a pic of the heart. It was a "heart Slinky." Unwound. I've never seen anything like it.
My daughter with the same rifle, same bullet, same result, last fall on BIG WI doe...
Deer took zero steps. In the shoulder, out the shoulder. Not sure what else you'd want from a .300 Mag let alone a .223 Rem.