I can't say I have. Apologies for the sarcasm in my last post. My only point was one of ballistics. Whether or not that tracking job is required has no dependency on a 6.5PRC being used as opposed to a 7mm. A 6.5PRC is more than adequate to take down a Marco Polo sheep under the conditions you mention. I do question taking a shot at a running sheep at over 250 yards in a snowstorm with any caliber though. But we all have different abilities. I don't practice at running animals so I don't take those shots personally.