This is what WIKIPEDIA says:
The original intent of its designers was to offer a cartridge that could approach the ballistics of the .30-06 Springfield, while at the same time utilizing a smaller case that could be cycled through a short-action lever rifle. Although it fell somewhat short of its ballistic goals (by about 150 ft/s), its performance outclassed other contemporary .30 caliber lever-action cartridges including the .30-30 Winchester and .30 Remington. It soon became a popular deer and medium-sized game cartridge among North American hunters, and by mid century nearly every major US firearms maker offered a .300 Savage chambering in at least one of its rifle models.[2]
The .300 Savage distinguished itself further by serving as the parent to the .308 Winchester (7.62x51mm NATO) cartridge, a round that was developed for the US armed forces in the 1950s and which is still in use today.[3]
The Savage Model 99 lever-action rifle is no longer in production, and over the past two decades or so the .300 Savage has faded in popularity, eclipsed by its own progeny the .308 Winchester and other more powerful short action cartridges. However, it continues to be marketed by several ammunition manufacturers.
Ironically, Savage Arms no longer regularly offers a rifle chambered for what may be the most famous cartridge the company ever developed. Despite its decline as a sporting round, the .300 Savage remains quite popular with handloaders who are able to utilize newer smokeless powders and more aerodynamic bullets to obtain optimum performance from it.[
