If you ask ten different deer hunters what the best deer rifle is, you are probably going to get at least 5 different answers. I have heard at least this many throughout my lifetime. There is probably no definite answer when it comes to which is the best, but the most popular is the .30-06 Springfield. More people choose this as their deer gun than anything else. Sometimes the best deer rifles are what the individual likes the best, but sometimes the best one depends on where you are hunting and where you are aiming.
When it comes to choosing a gun for deer hunting, there are three things to consider. Distance, accuracy, and knockdown power. Some guns have more of one thing and less of the other. For example, and .30-30 Winchester is going to have plenty of knockdown power, but less accuracy and distance. On the other hand, a .243 Winchester will have more distance and accuracy, but less knockdown power. One reason the .30-06 is so popular is because it has a high rating of all three categories. A muzzleloader is going to have very little accuracy and distance but a ton of knockdown power. When it comes to deer, you will definitely need enough power to kill one, so small caliber guns like a .22 will not work. That is assuming you won’t be shooting them in the head.
Some people make their choice on a certain caliber because it is what a person they look up to hunts with like a father or famous hunter. Other people choose by where they are hunting. If you are hunting in some thick woods with a lot of brush, you will want a lot of knockdown power that isn’t going to be deflected by leaves or twigs as easily. In this kind of situation, rifles like a .30-30 Winchester or .30-06 are two of several that would be good. Some calibers like a .22-250 are easily deflected by leaves or small limbs. On the other hand, if you are hunting in an open field with a lot shooting room, you will need an accurate shooting gun with a long range. Calibers like a .270 or 7mm are good for this application. Even smaller calibers like a .243 or .22-250 are even good choices. These smaller calibers are some of the most accurate shooting guns you can get.
If you are one of those people who like a caliber just because someone else uses it, then I guess whatever makes you happy is best. If you are looking for a new gun for deer hunting, please use the objective approach and choose one based on how you plan on hunting. If you are not sure, then you can never go wrong with the ever popular .30-06. It will work in almost every situation.