口径逐渐收小之枪

例句：

1. 1. The gun has asmall caliber.
   这把枪口径小。
2. 2. The new rifle is larger than theold one.
   新步枪比旧的要大。
3. 3. The bullet was designed to fit thisparticular caliber.
   子弹是按照这个特定的口径设计的。