At some point before or early on in World War II, armies realised that they needed a mobile flak (or "Triple A") solution that could keep up with an armoured column and survive alongside it in a battle. Truck-towed AA was fine for some purposes and truck-mounted AA was good for others, but neither provided the ability to roll with the tanks and fight alongside them.

In the 60s the Americans found that missile systems like Hawk and Chaparral weren't so effective against low-level targets. Someone thought up the idea of sticking a 20mm rotary Vulcan gun on a standard M113 armoured personnel carrier, and the M163 Vulcan Air Defence System (VADS) was born. 

Like other such vehicles, it turned out to be even more effective at direct fire on ground targets than it was in shooting down low flying planes. It was used like that in Vietnam and in Panama.

But its original objective was to provide point defence and for that it had a ranging radar tied into a lead-computing gunsight. An operator sat in the open turret to engage the target.

Many countries have used, or still use, the M163, including South Korea, Egypt, Jordan and Tunisia, as well as a couple in South America. The Israelis upgraded theirs to have a Stinger SAM launcher on it. The US versions were mainly replaced by variants of the Hummer and M2 Bradley, each packing Stinger missiles. 

I picked this up on a whim and probably paid more for it than I had to. Not by much, though, so "whatevs", right?

It's a basic kit, cleanly moulded but with minimal detail. Maybe it is more aimed at the wargaming crowd than modellers. The cannon is moulded directly onto one half of the cupola or turret, and there is really no detail to speak of at all. Even the prominent bars you can see on the box illustration aren't there. 

Inside the M113 body itself there's a floor and some bulkheads, but nothing to represent the equipment that's inside an M163. 

Tracks are hard plastic and you assemble links around the curved parts front and back. Looks like a tedious job, but might be better than the rubbery tracks that blight some old tank kits (I'm looking at you, vintage Airfix!)

Decals look nice enough and there are markings for a Vietnam-era US Army version, an 80s US Army in Europe one, and a US and Saudi example from Desert Storm.

I've already started mine and it looks like it fits together nicely.