Recently we had a thread about RPGs and the consensus was that they are useless against a modern tank like the Abrams M1.
But how effective is the GAU-8 gun of the A10 against an Abrams?
Also is there a tank with better armor than the M1? If so, then how does it cope against the GAU-8?
Well for starters, the A-10 carries more than the gun. And it all depends on where you hit the tank.
Each round is significantly less powerful than your average RPG-7 shot, so take the same assumptions there and crank them down. Frontal hits negligible, side hits probably a mobility kill due to quantity, rear hits almost certainly a mission kill to engine loss. Crew would only be threatened on top hits, but you’re more likely to get that with an RPG from a rooftop than you would from an aircraft. Aircraft tend to not want to fly straight down.
The A-10 carries missiles like the AGM-65 to deal with battle tanks. The cannon is for softer targets.
So the A-10 typically won’t dive at tanks?
It dives at about a 30 degree angle. Also, the Warthog is firing over 60 depleted uranium rounds a second! These are some of the most advanced armor-defeating rounds on the planet. Certainly for their size. The Abrams fires a depleted uranium penetrator as well. It is much larger, but the Warthog’s gun fires 4,000 rounds a minute. This more than makes up for the smaller size.
The statement that the Avenger rotary cannon is only used on soft targets is insane. It is the primary armament of the Warthog… whose primary purpose is to kill tanks. That cannon is a purpose built tank destroyer and it will cause considerable damage to an M1 Abrams.
Talking about “where it hits” is also misleading. The Warthog is going to aim for, and hit the top of the tank. That’s what it does.
It’s going to to penetrate the top of the tank multiple times, leaving it in flames and everyone inside dead.
Wait, what do you mean by the word “powerful” here? Are you considering the relative speed assist from the jet’s engines?
It can dive considerably steeper than that. I have filmed an A-10 firing a AGM-65 Maverick missile in a 70 degree dive.
I read recently somewhere an assertion that late-model Abrams have reinforced top armor sufficient that the Avenger is no longer considered likely to pierce the armor at all (obviously damage to external hardware and tracks is still possible if that’s true). I have no cite however, as I can’t recall where I saw this claim.
Powerful as in estimated average penetration. Ballpark figures for a round from the GAU-8 at the middle of the engagement range is about 70mm RHA while an RPG-7 round is ~300mm. You’re comparing a 3 kg HEAT charge to a 1/3rd of a kg slug. It’s a different class of weaponry entirely.
The problem is that in a dive that steep, the time spent within cannon envelope is very brief. Guided weapons that can be lined up from a distance and fired from a much greater range are very different from rolling in, aiming, firing and pulling out in under two seconds. It’s one of those things that’s technically possible, but very much a hotshot maneuver of questionable wisdom.
Their size is the entire issue, though: it’s a 30mm cannon. It’s a very cool 30mm cannon, sure, but it’s still just an inert slugthrower. It’s a “tank buster” only in terms of the 1960s Soviet tanks it was made for, and there’s some debate about if even that wasn’t being overly optimistic. It services perfectly well at chewing up everything that’s not a main battle tank, which is the large majority of vehicle targets, but it’s not magic. The high rate of fire is the only thing that makes it threatening at all to a modern MBT, as it makes track and wheel damage likely from a side shot. Otherwise, it doesn’t matter how many times you shoot, if none of them breach the armor.
To put it in perspective, the round the M1 uses on other tanks is (at least) 25 times heavier and fired at half again the velocity, and anecdotal evidence from friendly fire in DS1 suggests that still wasn’t enough to penetrate another M1 from many angles.
Oh, I agree a 70 degree dive is not optimal for a gun pass. Probably wasn’t optimal for the missile shot either. I was an aerial photographer in a weapons testing squadron, and we were establishing the limits of performance for the weapon/airplane combination. That particular mission established that the weapon could be safely fired from a Warthog in that flight condition.
Let me add that a 70 degree dive is…sporty. I didn’t do many of them. Most dive missions I flew were 30 or 45 degree releases.
This thread is porn.
I have a question regarding the overall real world effectiveness of the A-10 in combat situations.
Given the rate of fire for the various guns, as noted above, it seems to me that the A-10 would be good for one burst with each of its guns before it was out and would need to return to base to reload.
If it happened that those bursts missed, then the combat effectiveness of that particular aircraft would be minimal.
Accordingly, to compensate for this, there would need to be a huge fleet of them in the air at any given time in the hope that a few of them would land hits.
Am I right on this? What is the real world experience with this?
No. The A-10 is capable of multiple short bursts from the gun. It also can carry a variety of missiles and bombs on the wings. A-10s were used to great effect during Desert Storm…especially against softer vehicle targets. The downside for A-10s is you have to have established control of the airspace before sending them into battle. They are vulnerable to fighters and air defenses.
It carries enough ammo to fire the gun for about 16.8 seconds.
16.8 seconds of Hell.
I saw one fire a less than one second burst at a gunnery range. It was like God threw a handful of gravel into a pond.
But it isn’t the entire issue. Not even close. You’re completely ignoring the rate of fire. Citing its single round penetration capability is like saying a sniper rifle and a mini-gun will cause the same amount of damage and penetrate the same amount of steel since they fire the same sized round. That isn’t true at all.
And the ballpark figure for 50 rounds placed in a 10ft radius?
Many angles? You mean the front, the left front, and the right front?
Still say the Abrams is done.
About 70mm 
The effects of armor degradation from multiple hits isn’t something that’s been studied exhaustively, to my knowledge, but the general view is that, unless you’re attacking reactive armor where relatively large chunks come off each time, you can’t expect to land multiple hits close enough to exploit the very tiny weakened area created by a previous hit. When the previous hits aren’t even remotely close to penetrating, it’s questionable if it makes any vulnerability at all. Your minigun vs sniper rifle analogy is pretty apt. A 7.62 rifle won’t get through a bank vault door, and neither will any amount of ammo fed through the minigun - but the minigun might really screw up any external mechanisms that the rifle can’t reliably expect to hit.
A 10-foot area of tank with about 20 35mm indentations? (The GAU-8 is accurate to within 80%/20ft radius)
Assuming a full burst at nominal range, I’d expect a full mission kill, mobility kill, tank operators likely unconscious with concussions and ruptured eardrums and who’ve just shat themselves. A-10 rounds have a tendency - I’ve read - to cause significant damage to the underside of the tank just from ricochets, so I guess the treads would go no matter which side it shot at. And, realistically, there’s a limit to how accurate you can be, moving in an aircraft at a kilometre’s distance. Hence the A-10’s philosophy of “I want to give everything in that general area one really fucked up day.”
What I wouldn’t expect is full armor penetration; neither the GAU-8 nor the ammunition it uses is meant to be current-day MBT armour penetrating. It’ll still do a hell of a job on whatever it points it’s gun at and there’s more to tank-killing than armour penetration - but there’s a reason it carries missiles as well.
I wish to agree with previous posters that this thread is absolute porn. Please keep the discussion going.