Sacred

from left to right:
7.62x54R, .308, 7.62x39, .223

Sacred

引用:

原帖由 M1616 於 10-10-2009 11:41 發表
MS..想問問有些彈頭中間有一行齒, 但有些又沒有? 唔明

that is called cannelure


http://en.wiktionary.org/wiki/cannelure
cannelure
Noun (plural cannelures)
2. Ringlike groove in the jacket of a bullet which provides a means of securely crimping the cartridge case to the bullet; analogous to the crimping groove in artillery ammunition.