I have to agree with Lawdog. In my very limited experience with 'yotes even at 400yds they often don't stand still for a very long period of time. At least not long enough for one to accurately judge the distance, dope the wind, make scope adjustments, draw a bead and squeeze. Really I think the limitation will be on the shooters part, the 32g and 40g .204 still has a significant amount of energy at 400yds to kill a 'yote, but the shot would need to be a very clean heart or lung to drop it.