bullet core

例句：

1. 1. The bullet core is the part of the bullet that holds it together.
   子弹核心是子弹中保持其在一起的部分。
2. 2.The bullet core was made from a special alloy.
   子弹核心是由一种特殊的合金制成的。
3. 3.The bullet core is designed to be small enough to fit into a gun barrel.
   子弹核心设计得足够小，可以放入枪管中。