Six millimetres is the same as.236 inches. To go from millimetres to inches, divide the number of millimetres by 25.4, which is how many millimetres are in one inch. Six millimetres is almost exactly one-quarter of an inch, or about.014 inches short.
The term “6 millimetre calibre” refers to a number of different types of ammunition. A calibre is a way to measure how big the inside of a gun barrel is and how big the bullet is that goes through it. Even though the different rounds of ammunition are called “6 millimetres,” the diameter of their bullets is usually 6.17 millimetres or more.