I have been using 243 for deer for over 30 years. Best bullet for reloading in my experience is Sierra 100 gr ProHunter. Damage to organs is reliable yet the bullet holds together enough to exit even on shoulder hits. For early years I used Remington 100 gr Corelok in factory ammo with no complaints. In current rifles (T/C Venture and Weatherby Vanguard), I am using Hornady 95 SST because of terminal performance and good accuracy. Very good bullet for deer. The Hornady SST factory ammo is not accurate in my Remington 700 rifle. I have not had a factory or a handload that was dependable for good blood trails. A 243 does not usually make a large hole. In the area where I am permitted to hunt, a deer traveling over 100 yards may be on private land where owner is against hunters. A dead deer down within 40 yards is a very good situation.