One advantage to reloading is the ability to adjust the load ballistics. This is especially true with today’s powders.
In the past, available reloading powders allowed the velocity of factory ammunition to be obtained. In most cases higher than factory velocity came with the risk of higher pressure. Today there are powders readily available that allow the reloader to exceed “standard” velocity levels by 100 fps to 200 fps. This is a benefit for the varmint hunter and long-range shooter where bullet drop becomes a factor.
Take the venerable 22-250. Historically, this caliber has produced 3,650 fps with a 55-grain bullet. Looking at the Hodgdon Reloading Data Center, there are at least 6 powders that allow this velocity to be increased up to 3,855 fps – just over 200 fps higher.
If you are interested in higher velocity, look at the factory ballistics for the load of interest in your caliber. Then go to the Hodgdon Reloading Data Center and look up the reload data for that caliber and bullet. In many cases, you will find a powder listed which will allow you to safely improve over the factory ballistics.