This Reads Like Raytheon and Lockheed Are Feeding Press Releases

But it could be true and if so, hurray for Javelin and the courageous Ukrainians using them.  3/4/22 NDTV:

The Ukrainian military fighting the much larger Russian invasion force has been able to kill hundreds of Russian tanks and armoured vehicles using a hand-held anti-tank missile supplied by the US, according to a US journalist who has been tracking the war in the east European nation.

At least 280 Russian armoured vehicles have been destroyed with the American Javelin missile, out of 300 shots fired, journalist Jack Murphy said in an article quoting a US Special Operations official.

That is a 93 per cent kill rate.

The Javelin, made jointly by Raytheon Missiles and Defence, and Lockheed Martin, follow a flight path that hits targets from the top, where the armour is relatively weaker. Almost every tank armour is thicker on the sides, but the top is known to be weaker, and that is where the Javelin missile strikes.

The Javelin can also be fired in a straight flight path mode, if needed.

"The first shipment of Javelins arrived (in Ukraine) in 2018, the weapons systems along with a training and sustainment block (called the Total Package Approach) totalling somewhere around $75 million," Mr Murphy wrote in the article.

I certainly see a lot of destroyed Russian armor in videos.  Not 280, but enough to find the number believable.  3/3/22 Forbes:

The Forum on the Arms Trade has been keeping track of all the weapons transfers to Ukraine announced so far. Looking just at portable anti-tank weapons, the list of what has been promised by different countries so looks like this, in descending order of numbers:

Sweden: 5,000 AT4 anti-tank weapons,

Denmark: 2,700 anti-tank weapons,

Norway: 2,000 anti-tank weapons

United Kingdom: 2,000 NLAW short-range anti-tank missiles

Finland: 1,500 single-shot anti-tank weapons

Germany: 1,000 anti-tank weapons

Netherlands: 400 rocket-propelled grenade launchers

Belgium: 200 anti-tank weapons

Estonia: Unspecified number of Javelin anti-tank missiles

This makes a total of some 14,800 weapons, on top of Ukraine’s existing equipment.

In the coming battle for the cities of Ukraine, such weapons are likely to be decisive. Russia does not have a significant advantage in terms of manpower on the ground, and will be relying on the firepower and protection provided by armored vehicles to tip the balance. In urban combat though, tanks and other vehicles are extremely vulnerable to short-range anti-tank weapons. They are also some use against troops holed up in buildings.

If even half of those weapons are used again armored vehicles, the Russian tank crews are going to be scarcer than Russian tanks.  Molten metal exploding into the confined space of a tank seems unsurvivable. 

Also of interest in that Forbes article:

Oryx further analyzes the images to validate its authenticity and determine the make and model of each piece of equipment. A large amount of the equipment on both sides are remnants of the Soviet era. This aligns well with reports about a stagnant Russian defense industrial base, from whom both sides buy their equipment, and underfunded militaries. While if properly maintained, the equipment would be expected to operate without issue; however, approximately 15 percent of the equipment listed on Oryx was abandoned. About half of the vehicles appear to have been abandoned due to maintenance issues, with nothing else appearing wrong with the vehicle in its images.

Further, many of the abandoned vehicles appear to have gotten stuck in the mud. Tanks and armored vehicles are naturally heavy, and although tracks help with mobility, they can still get stuck. Since it is early spring in the Ukraine, the ground is unfreezing and getting muddy. The weather and terrain are forcing the Russian forces to stick to the roads, as seen in the “40-mile convoy” heading to Kyiv. Unfortunately, roads provide little cover or concealment and make the vehicles easy to target. Furthermore, obstacles in the roads or a destroyed bridge can result in backed-up traffic which further helps leaves the vehicles in a vulnerable position.

3/10/22 New York Post has drone footage of Russian armor going boom!