Thanks for the response Oldtimr! Many of the deer being chased by dogs are actually quite calm, especially when the deer is way ahead of the dogs. Oftentimes, a mature buck will get really far ahead of the dogs and just creep through the woods, stopping to smell and taking his time before deciding to cross fields or paths. Sometimes, the dogs are really close, and in your words, the deer is running flat out but that usually doesn't last long once the deer has put some space between it and the dogs. I've always used buckshot when hunting deer with dogs, but not because the deer are running through thick areas. I just grew up hunting with a shotgun and buckshot so that's what I'm comfortable using. Many dog-hunters use rifles or shotgun slugs. Like most hunters, I don't shoot what I can't see. I don't shoot at a deer when it's running through thick cover and I can barely see it. We look for holes and openings in the woods and take smart shots where we know we can kill the deer. Oftentimes, the deer stops when it sees you and that's when you take a good clean shot. Other times the deer is just loafing through the woods at twenty yards and it's not very difficult to harvest a slow moving deer at 20 yards with a shotgun when somebody has been doing it for 20 years. Thanks again for the response Oldtimr! Good luck hunting this year!