The .243 is ideal for game weighing between 90-130lb but is also adequate for 180 lb big game animals. This weight limit is suggested not because the .243 cannot produce sufficient penetration on larger game, but because with rear lung shots, even though wounds may be free bleeding, kills can be so slow as to allow animals to run considerable distances and become lost altogether to the hunter. On heavy boned deer and elk careful shot placement is the key. Countless Elk have been successfully harvested with the .243 without fuss. However, for every success story there are just as many failures. While many experienced hunters like to argue the limitations of the .243 based on their own skills, animal welfare should always be paramount. There are a great many calibers more suitable for larger game than the .243. Have him practice with the 30 06. He might like it better and even shoot better with it. He is 16 and he can make his own final decision.