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Independent military history author and researcher. Coffee tips are appreciated! https://t.co/t1EjNrIZ2c Now also at https://t.co/4qGQ2ffHJJ

Sep 7, 2022, 22 tweets

1/ Why is visual confirmation that Ukraine now has M982 Excalibur artillery rounds in its inventory such a big f'ing deal, as a certain US president might say? A 🧵 on why Russia might well need to fear Excalibur more than HIMARS.

2/ This video shows a Ukrainian soldier using an Enhanced Portable Inductive Artillery Fuze Setter (EPIAFS) to program Excalibur rounds with target coordinates (h/t to the eagle eye of @noclador for spotting it).

3/ A donation of Excalibur rounds by Canada was reported way back in April. The US media also reported planned future donations of Excalibur in July/August. But as far as I know this is the first published visual evidence that they're now actually in use in Ukraine.

4/ Excalibur is a Swedish-US 155mm artillery round that can be fired from a range of NATO-standard artillery systems. It's GPS-guided, gliding on folding fins from the top of its ballistic arc onto its target. Before firing, the target coordinates are set using the EPIAFS system.

5/ Excalibur is extraordinarily accurate, with a circular error probable (CEP) of only 5m. (In testing, 1.6m CEP was achieved.) It effectively turns 155mm howitzers into oversized sniper rifles capable of picking off individual targets from tens of kilometers away.

6/ To understand why this is so significant, let's dip a little bit into the concept of CEP. It's simply a circle within which 50% of shots will land. Another 43.7% of shots will land within a wider circle equivalent to twice the radius of the first 50%.

7/ So in the case of Excalibur, if CEP is 5m, 50% of shots will land within that distance of the target, 43.7% will land within 10m and 6.1% will land within 15m. Only 0.2% will land further away.

8/ In reality, you'd need far fewer Excalibur shots to achieve the desired effect. Its maker Raytheon says: "it can take at least 10 conventional munitions to accomplish what one Excalibur weapon can".

9/ Let's consider the real-world impact of this using the T-72 tank. A T-72 hull is 6.95 m long by 3.59 m wide. Here's what it looks like (roughly) superimposed on the 5m CEP of an Excalibur round. 93.7% of shots are either going to hit it directly or impact within 8m at most.

10/ It's game over for our T-72 if it's hit directly from above by a 155mm round. 22kg of high explosive landing at hundreds of metres per second or bursting overhead can make a mess of a lot of things, including a tank's top armour and the crew inside.

11/ But even a near miss can also cripple a tank and injure or kill the crew. Tests by the US Army in the 1980s showed that severe damage can be caused by a 155mm round exploding as far as 30m away. In one test against dug-in tanks and APCs, near-misses caused devastating damage.

12/ 50% of the targeted vehicles were disabled and 50% of the simulated personnel were wounded or killed. Tank wheels and tracks were wrecked, immobilising them; guns were made inoperable; engines and gears were damaged; crew compartments were pierced by fragments.

13/ (For more on the effects of near misses on tanks, see the thread below.)

14/ Excalibur's accuracy enables the Ukrainians to go from targeting the general vicinity of Russian tanks to dropping shells directly on the tanks themselves. Or they could go from targeting buildings to targeting the individual rooms of those buildings.

15/ This level of accuracy offers other useful possibilities. It permits close artillery support at ranges within 75–150m of friendly troops, which wouldn't normally be possible without severely endangering them. Or it could be used for precision strikes in civilian areas.

15/ The other crucial point about Excalibur is that its range is longer than conventional artillery rounds. Depending on the barrel length (caliber), Excalibur's range varies from 40 to 70km. M777 howitzers can fire it up to 40km, CAESAR and Krab can fire it up to 50km.

16/ Ukraine has vastly more 155mm artillery than it has HIMARS or M270s – 200+ 155mm artillery systems compared with 25 HIMARS/M270s, according to @oryxspioenkop's figures. This gives it far more options for using Excalibur rounds. oryxspioenkop.com/2022/04/answer…

17/ HIMARS/M270 has longer range and even greater precision, but its usefulness is limited by the small number of launchers donated so far. That's a major limitation on a front line that's 2,400 km long. 200+ 155mm systems armed with Excalibur can cover a far wide area.

18/ Also, while HIMARS rockets can potentially be intercepted (Russian claims of having done so are disputed), artillery rounds are much harder targets. As far as I know Russia doesn't have a land-based equivalent of the US C-RAM system.

19/ So, in short, with Excalibur confirmed to be in play, Russia's forces in Ukraine can expect to have many more 'smoking accidents' and unexpected 'arrivals'. /end

(@kimmojvs, does this answer your question? 😁)

US donations of Excalibur now publicly confirmed: bloomberg.com/news/articles/…

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