In French the word rifler meant to "scratch" and that's why the grooves inside a gun barrel are called rifling.

法语单词rifler就曾经有“刮”(scratch)的意思，这也就解释了为什么枪膛内的膛线被称为rifling。

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A gun barrel was made of this new "chromium steel" but the first shot fired through it broke it into a dozen pieces.

用这种新的“铬钢”做成的枪，第一次开大后它就裂成了许多碎片。

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The utility model discloses an aerial power transmission and distribution wire ice removing device comprising a gun barrel.

本实用新型公开了一种高空输变电线路除冰装置。

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The bill seemed to curl up as if it had been rolled and stuck into the end of a gun barrel.

VOA: special.2009.11.14

"All politics grows out of the barrel of a gun," as a famous twentieth-century Machiavellian once put it.

所有的政治都是活在枪杆子下“,这是二十世纪一位著名,马奇亚维利派学者的解译。

耶鲁公开课 - 政治哲学导论课程节选

"But,the point of the international community is that those are not to be dealt with at the end of the barrel of a gun, but,instead,through legal proceedings."

VOA: standard.2009.07.03

She said she was holding her husband by his life vest with one hand and her Sea-Doo with the other when she found herself staring down a gun barrel.

CNN: A 'stupid' mistake or murder?

Viewers and readers were intrigued by the shots of the outdoorswoman with her eyes squinting fixed along a gun barrel, the thought of a vice president who had once been a beauty queen.

CNN: Europe mocks 'half-baked Alaskan' Palin

Any electron passing along such a wire should be able to travel ballistically (that is, without being slowed down by bumping into any atoms in the wire, just as a bullet travels down the barrel of a gun).

ECONOMIST: Spintronics