Whole Nine Yards

[Douglas G. Wilson]

>The only aircraft that I've found that carried 500 rounds of .50 caliber
>ammunition per gun, which would put belt length at just around 27 feet is
>the P-38L Lightning ....
>
>For me, though, the chief argument against this explanation is that
>ammunition is not measured by the length of the belt. Belt segments can be
>attached and detached to create belts of any length ....

I don't know much about ammo, but .50 cal. shells which I've seen were
shaped like bottles, with the bullet about 0.5 inch in diameter but the
shell casing (which must be accommodated in the belt) considerably larger.
There may be some variation in type of shell, but one Web site gives the
maximum (casing/rim) diameter of a Browning .50-cal. machine gun shell as
0.804 inch.

Belts can be of any length but there are/were of course various military
standards. I am told that the ammunition for the .50-cal. machine guns on
Hellcats and Corsairs (naval fighters) around 1950 was conventionally
provided in the form of a drum which contained a belt of ammunition (for
each gun). Web sources give the standard .50-cal. ammunition load for these
planes as 390 rounds per gun. Taking this example, assuming, say, 1/2 mm
spacing (= 0.02 inch) between rounds (so they won't rub together), one
would require about 0.824 X 390 inches for each gun's belt length ... that
is, about 321.3 inches. Nine yards = 324 inches, so it would be reasonable
to call this a nine-yard belt.

I believe the actual length of the belt is not entirely relevant; what is
significant is whether the belt was CALLED "nine yards". Since the belt
stayed folded inside the container (drum or compartment) until expended --
it wasn't flopping around inside the plane or hanging out in the breeze --
I suppose there would be no reason for anyone except MAYBE an ordnanceman
to concern himself with the belt's length. OTOH, I presume that a lecture
at flight school or somewhere would have included some information about
how the ammo was fed, etc., probably including some remark about how long
the belt was for each gun.

I think the "ammo-belt" etymology story is perfectly believable. Whether
the story is true is a different question.

-- Doug Wilson