The standard ammunition mixture for anti-armor use is a five-to-one mix of PGU-14/B Armor Piercing Incendiary, with a projectile weight of about 14.0 oz (395 grams or 6,096 grains) and PGU-13/B High Explosive Incendiary (HEI) rounds, with a projectile weight of about 13.3 oz (378 grams or 5,833 grains).[9] The PGU-14/B's projectile incorporates a lightweight aluminum body, cast around a smaller caliber depleted uranium penetrating core.

The Avenger proved lethal when tested against M47 Patton tanks in 1979.

Lethal.

Cool, but what's the "BRRRRT" noise about?

That's the pilot trying to keep their colon's clenched as they fire. The shaking is so massive sometimes they squeeze out some fear farts. =)

It's the A-10's gun firing at 4200 rounds per minute, 70 per second:

The General Electric GAU-8/A Avenger is a 30mm hydraulically driven seven-barrel Gatling-type cannon that is typically mounted to the United States Air Force's Fairchild Republic A-10 Thunderbolt II. It is capable of firing 4,200 rounds per minute.

Here is a gun test of the system:
https://www.youtube.com/watch?v=33teK7L4DM4

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