And the ubiquitous 7.62x51mm NATO caliber is essentially indentical and fully interchangeable with the the classic .308 Winchester civilian cartridge. No it isn't. A chamber designed for 7.62X51 will handle a .308 fine. The converse is not true. My .308 bolt guns require real .308 made by Federal or Winchester. A 7.62X51 will not settle into the chamber. You haved lived (or nearly died) until you have a 7.62X51 NATO do a slam fire as you push the bolt forward.
A chamber designed for 7.62X51 will handle a .308 fine. The converse is not true. My .308 bolt guns require real .308 made by Federal or Winchester. A 7.62X51 will not settle into the chamber.
Factory rifles do not normally have this problem. If you have some custom tuned rifles, they may be limited to certain narrow range of cartridge lengths. Your slam fire problem may be for different reasons.
Here is a widely-cited article on the arcane subject you may find interesting:
http://www.fulton-armory.com/308.htm