Standardized in 1945, the 7.62×39mm was invented to do the same job the 8mm Kurtz did for Germany; provide an intermediate round that would be effective and versatile. Later chambered in the AK-47, the 7.62×39 has become the most successful and widespread battle-rifle chambering ever adopted. With far better battlefield effectiveness than any version of the 5.56 NATO, the 7.62×39mm has also become the basis of a plethora of modern chamberings beginning with the most successful benchrest round of all time, the PPC. This resulted entirely from the fact that Lapua made the most uniform, concentric cartridge cases in the world as the 220 Russian, which is simply a necked-down version of the 7.62×39 to use and odd-ball 0.221-inch diameter bullet. Originally designed to use 0.311-inch diameter bullets, bore size has been standardized in the U. S. to use 0.308-inch bullets. While apt to be relatively inaccurate, ammunition loaded with 0.308-inch bullets can safely be used in earlier guns with the 0.311- to 0.312-inch groove diameter; the converse might not be true. Usually, the gun allows ample space for cases loaded with the larger bullet to freely chamber and space for the bullet to move a bit before it must swage down to fit the smaller bore. But, no doubt, combinations exist where the larger bullet would cause interference in the newer chamber and therefore result in high pressure. Use due caution to avoid this situation. Similarly, steel-cored bullets of 0.312-inch diameter are likely to cause high pressure when fired in the smaller bore. Loaded with the best modern components, the 7.62×39 can approach typical 30-30 ballistics and is, therefore, suitable for anything the 30-30 is suitable for. When loaded with efficient pointed bullets, it can outperform the 30-30 beyond 50 yards or so.