If you read enough about guns, and talk enough about guns with other gun people in person or on the Internet, you’ve probably heard about a powerful “shockwave” produced by the uber-powerful .50 BMG rifle round fired from a Barrett sniper rifle, or the like.

The story goes that a .50 cal. round creates such a “shockwave” as it moves through the air that it can kill a man, or rip a limb off, merely by passing by close enough.

Now, anyone who knows anything about physics, or even looks up “physics” on Wikipedia, will realize after thinking about this a bit, that it can’t be true. Even if you’ve read or heard the story, you’ve likely heard other stories dispelling it. Even accounts from soldiers intimately familiar with the .50 BMG round fired from rifles and heavy machine guns say a hit is a hit and a miss is still a miss, even with the big .50.

A half-inch diameter bullet does create a small shockwave when it breaks the sound barrier, but its doesn’t generate a significant force. When the MythBusters did an experiment to test out the effect of shockwaves on glass, the .50 BMG failed to break glass merely by passing by it. In fact, they couldn’t get an F/A-18 going supersonic at flybys of 8,000, 2,000 and 500 feet to damage the glass either. And that’s a lot bigger than a bullet.

So, if you need any more proof, link to the video above. If a .50 caliber round can tear pieces off a man by passing by his body, it surely will knock over a house of cards or plastic cups…when fired through them, at close range. Right?

But don’t let any of this fool you. The round is extremely powerful, with an 800-grain bullet generating around 15,000 ft-lbs of energy. Canadian Army Corporal Rob Furlong of the PPCLI shot a Taliban combatant at 2,657 yards with a McMillan Tac-50 chambered in .50 BMG during the 2002 campaign in the Afghanistan war. Until 2009, it was the farthest confirmed kill on the books.

In 1967, U.S. Marine sniper Carlos Hathcock set a record for a long-distance kill at 2,286 yards with a .50 BMG fired from the weapon it was designed for, the M2 Browning Machine Gun, equipped with a telescopic sight and with its cycling mechanism adjust so low it was effectively semi-auto.

If you want to know where the .50 BMG might be headed, read about the EXACTO program here (that stands for EXtreme ACcuracy Tasked Ordnance). It’s a sniper rifle that has been in the works by Lockheed Martin and Teledyne Scientific and Imaging since 2008. It would fire .50 BMG rounds with bullets equipped with “fin-stabilized projectiles, spin-stabilized projectiles, internal and/or external aero-actuation control methods, projectile guidance technologies, tamper proofing, small stable power supplies, and advanced sighting, optical resolution and clarity technologies.” That means a bullet you can steer, or that can be guided to its target.