Few sports are as American as football. Pretty much everyone raised in this country has bound to have laid their hands on a football at one point or another. So this gave the folks at U.S. Army's Land Warfare Laboratory (LWL) an ingenious idea for an anti-tank grenade.
The plans for the "football device" were hatched in LWL's Aberdeen proving ground in Maryland in July 1973. There were concerns about the efficacy of existing anti-armor measures, especially in urban settings. The U.S. was concerned they might have to get into a conflict with the Soviets in Europe at the time.
According to the Drive’s article, standard-issue anti-tank weapons in the Army were BGM-71 TOW and FGM-77 Dragon—which were anti-tank guided missiles and variants of the M72 Light Anti-Tank Weapon (LAW). But LWL thought these weapons had one big common issue. Firing them meant you gave away your exact position. Besides, projectiles from these launchers did not arm themselves until after traveling a certain distance so as not to put the operator or any friendly standing along the line in jeopardy. So, a close-quarters combat scenario with these was not a desirable thing.
There were some other improvised solutions to this, but let's not get sidetracked here.
LWL decided a hand-thrown device with a shaped charge was the way to go. Like a warhead, or rocket. A shaped charge is sometimes also called a hollow charge. It has a large open cavity between the front side of the projectile and the main explosive. This way, when the explosive detonates, it expands out towards the front, turning the projectile into a high-speed dart.
This part is not new, it's been used since the late 1800s since it simply works. But the forwards part of the projectile has to face towards our target, or else the explosion dissipates towards the wrong way.
Why a football, exactly?
LWL's 1974 reads "Since a regulation size football weighs 14 ounces, it was considered feasible to make a shaped charge grenade within this weight limitation," and what's more "most US troops are familiar with throwing footballs."
When you put it that way, the idea makes perfect sense. Footballs are intended to be thrown long distances and when thrown properly, they stabilize during flight. Army manuals estimate that an average soldier can lob grenades 38 yards (35 meters) away, NFL quarterbacks throw further than that regularly. While we cannot expect non-athletes to throw that far, it's bound to improve things a little, yes?
Eventually, this design never saw the light of day and was never deployed in the field. You can ask why that is to anyone that has seen a football bounce after hitting somewhere. Plus footballs are hollow inside, their skin is what stabilizes them mid-air, and if you fill it with an explosive rig, that's bound to cause weight imbalances. All in all, they couldn't get the device to reliably penetrate armor. The football would bounce before detonation too, causing more loss impact-wise.
And the company Nerf eventually came to be known for their foam-bullet launchers rather than quirky war-time contraptions.
H/T The Drive