Stats for GAU-8 Avenger?

[Belial666]

The GAU-8 Avenger is the seven-barrel, 30mm rotary cannon used in the A-10 planes. It weighs 280 Kg, with another 1700 Kg for feed system and maximum ammo. Gun length is 2,85 meters, total length with feed system is 6 meters. It can fire up to 4200 rounds/minute at muzzle velocities of 1.070 m/second. Effective range is 1.200 meters, max is 3.600 meters. Standard ammunition is 30x174 mm, either PGU-14/B Armor Piercing Incendiary at 395 grams with aluminum body and DU core or PGU-13/B High Explosive Incendiary at 378 grams.



So what kind of damage and armor divisor would this have in GURPS terms? What would be the minimum ST rate to carry it around and use it effectively?

EDIT: and how could somebody put a large percentage of the rounds in a tank-sized target given GURPS mechanics for high ROF?

[Ulzgoroth]

Originally Posted by Belial666

EDIT: and how could somebody put a large percentage of the rounds in a tank-sized target given GURPS mechanics for high ROF?

Only by not taking advantage of the high ROF. Which might not even be doable with this cannon.

There have been a number of threads about that type of question and houserules to address it.

I'd raise another point: under GURPS rules there's no way to use a fixed gun like this accurately under any circumstances. The pilot cannot Aim while flying the plane. I don't think they can even All Out Attack. You're going to need that RoF bonus.


...And one step further, does anyone actually put a large percentage of shots from such a gun on target? My expectation would be that that is not the point and not practically achievable.

[Nereidalbel]

Originally Posted by Ulzgoroth

...And one step further, does anyone actually put a large percentage of shots from such a gun on target? My expectation would be that that is not the point and not practically achievable.

Not at any appreciable range. It's one of those weapons designed to spray death over a large area.

[sir_pudding]

Originally Posted by Ulzgoroth

...And one step further, does anyone actually put a large percentage of shots from such a gun on target? My expectation would be that that is not the point and not practically achievable.

The entire reason that aircraft cannon have such high rates of fire and large bullet spread is to increase the chances off hitting a target with large relative motion to the firing platform.

[Anaraxes]

70 rounds per second isn't that high if you're moving 2 meters between shots -- or pitching your aim axis by a degree between each, for that matter.

The RoF isn't to hit a single target many times. It's to rack up a big bonus to hit to make up for all the minus from the moving firing platform.

[ColBosch]

It's part of why the USAF is not impressed with the A-10, though it is appreciated for its huge hardpoint capacity and sheer survivability.

I'm sure there are no 4e rules for the GAU-8/A, so can't help you there, but I did have a pilot once tell me that they take advantage of the Warthog's stability when attacking with the main gun. It's not Aiming, by GURPS rules, but it is an All-Out Attack. They line up the nose short of the target and concentrate for a second as they walk a line of rounds into the target (and yes, out of each burst, only a handful of rounds impact). They then pull the nose up and evade; the point of the Thunderbolt II's strong armor is to protect it during the attack run.

There are MANY videos on YouTube that show the A-10 in action. This is a pretty short run that illustrates what I was saying:
https://www.youtube.com/watch?v=eCnjWmtfvFo

Note how short the burst is (a second, maybe two), the line-up-attack-and-evade pattern, and the sheer number of rounds that clearly miss (fall short and overshoot) the targets. Also note that you first hear the rounds strike the target, then the sound of the weapon firing - the GAU-8/A's 30mm rounds are supersonic.

[Belial666]

The accuracy of the GAU-8/A, installed in the A-10, is rated at '5mil, 80 percent', meaning that 80 percent of rounds fired at 4,000ft (1,800m) will hit within a circle of 20ft (6.1m) radius.


Of course, that's a lot bigger than a tank but still...

[Ulzgoroth]

Originally Posted by Belial666

The accuracy of the GAU-8/A, installed in the A-10, is rated at '5mil, 80 percent', meaning that 80 percent of rounds fired at 4,000ft (1,800m) will hit within a circle of 20ft (6.1m) radius.


Of course, that's a lot bigger than a tank but still...

The accuracy of the gun is not the problem in this context. In theory it should be possible to score lots of hits with that gun under appropriate circumstances. GURPS probably has a problem there, and one which as I said is extensively discussed.

But when the gun is embedded in a flying airplane the accuracy of the gun itself is not the problem. You're not going to score a high hit rate regardless because you won't have the gun pointed in the right place for most of the duration of the burst.

[HANS]

I've answered the very same question here.

Cheers

HANS

[ColBosch]

Originally Posted by HANS

I've answered the very same question here.

That helps. Thanks, Hans!

Of course, this still leaves the question of whether or not the pilot can take an Aim or All Out Attack maneuver. It is spinal-mounted and has a gunsight, so...maybe?