Don’t have the 204 in a ar but I do have one in a tc pro hunter and I believe that is the most fun round I own to shoot. The best thing I’ve ever shot with it was a crow at about 75 yards walking away from me . Held dead center of its back and all I found was wings . The 40 gr v max is devestating. I’ve killed rabbit ,turkeys,ground hogs ,crows and even deer with it . Got it and my buddy who had one since it first came out told about a horrible experience with a deer with his . Saw him after deer season and let him know that I’d killed 2 with mine and maybe he needed to learn to shoot . He said where did you shoot them at my response was as honest as the day is long “ in the right eye “ . Shockingly enough neither did anything other than fall straight to the ground like struck by lighting. And their heads were a skull of jello. It’s all about shot placement!!!