As a firearms expert with extensive knowledge in ballistics and ammunition, I can provide you with a detailed comparison between the 7.62x39mm and .308 (7.62x51mm NATO) cartridges.

English Answer:
The 7.62x39mm and .308 (7.62x51mm NATO) are not the same. They are two different cartridges with distinct characteristics:


1. Case Dimensions: The 7.62x39mm has a shorter case length compared to the .308. The "39" in 7.62x39mm refers to the case length in millimeters, while the "51" in 7.62x51mm indicates a longer case, which typically allows for more powder and potentially higher velocity.


2. Bullet Diameter: Both cartridges have a bullet diameter of approximately 7.62mm (0.3 inches), but the actual bullet profiles and weights can vary, which can affect performance.


3. Ballistics and Performance: The .308 generally has a higher muzzle velocity and energy due to its larger case capacity, which can translate to flatter trajectories and better long-range performance. The 7.62x39mm, while still effective, is often considered to have less long-range potential and lower muzzle velocity.


4. Chamber and Rifling: Rifles chambered for one cartridge are not necessarily safe to fire the other. The differences in case dimensions and pressure specifications mean that using a .308 in a 7.62x39mm chambered rifle or vice versa can be dangerous.


5. History and Usage: The 7.62x39mm was developed for the SKS and AK-47 rifles and is widely used in many Eastern Bloc countries. The .308, on the other hand, is used by NATO forces and is often found in bolt-action rifles for hunting and long-range shooting.

中文回答：
7.62x39mm 和 .308 (7.62x51mm NATO) 是不同的两种弹药，它们具有以下不同的特点：


1. 弹壳尺寸：7.62x39mm 的弹壳长度比 .308 短。"39" 指的是弹壳长度，单位是毫米，而 "51" 则表示更长的弹壳，通常允许装填更多火药，可能带来更高的初速。


2. 子弹直径：两种弹药的子弹直径都大约是 7.62mm（0.3 英寸），但实际的子弹形状和重量可能不同，这会影响其性能。


3. 弹道和性能：.308 通常具有更高的枪口初速和能量，由于其更大的弹壳容量，这可以转化为更平直的弹道和更好的远距离性能。而 7.62x39mm 虽然仍然有效，但通常被认为远距离潜力较小，枪口初速也较低。


4. 枪膛和膛线：为一种弹药设计的步枪并不一定能安全地发射另一种弹药。弹壳尺寸和压力规格的差异意味着在为 7.62x39mm 设计的枪膛中使用 .308 或反之可能会很危险。


5. 历史和用途：7.62x39mm 是为 SKS 和 AK-47 步枪开发的，在许多东欧国家广泛使用。而 .308 则是 NATO 部队使用的弹药，通常在狩猎和远距离射击的栓动步枪中找到。

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If you're using ".308" to mean .308 Winchester, then no, they're not the same at all. .308 Winchester is very similar to the 7.62x51 NATO cartridge, but is loaded to higher pressures. If you are asking about the bullet in a 7.62x39, then yes, it's actually .312 in diameter.read more >>