Problems with what Benny !? Are you talking reloads or factory ammo...? Are you talking any specific loading...? Or are you talking the interchangeability of the two cartridges in the X-Bolt ...?!
Although not identical, the 7.62×51mm NATO and the commercial .308 Winchester cartridges are similar enough that they can be loaded into rifles chambered for the other round, but .308 cartridges are typically loaded to higher pressures than 7.62x51mm cartridges. Even though the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) does not consider it unsafe to fire the commercial round in weapons chambered for the NATO round, there is significant discussion about compatible chamber and muzzle pressures between the two cartridges based on powder loads and wall thicknesses on the military vs. commercial rounds. Therefore...I would tread lightly and be very sure the savings are worth the firearm ( or worse ) being damaged.
