SCFox
The Sierra X18 is one of many models that Shakespeare had on the market. There are many of them out there. They are not too valuable, but good solid shooters. Shakespeare made good solid bows that were a bitmore affordable than some of the more popular bows of their time.
As time goes on, your son will increase his draw weight. many people like to hunt with bows of 60 lbs and over. I stands to reason that the higher the draw weight, the more "punch" a bow will have. However, back in the '60's, there were more 45# bows in the hunting field than any other weight, and they took their fair share of game, including deer. I preffer to hunt with 50# and above, but I cannot discount the killing power of a 45# bow. If you have very sharp broadheads, a well placed arrow wil ldo the job out of a 45# bow.