Seven months ago, the Kremlin began pulling out of long-term storage BTR-50 tracked armored personnel carriers, up-arming them in some cases and sending them toward the front line in Ukraine.

It was a remarkable development. The BTR-50 is old. As its designation implies, it was designed and first fielded in the 1950s.

And while the modern Russian army hung on to a few specialized BTR-50 variants for support roles, for front-line roles it long ago replaced the aged, vulnerable APCs with much-improved wheeled BTR-60s, BTR-70s and BTR-80s. There even are a few experimental BTR-90s with combat forces in Ukraine.

But after 21 months of hard fighting that has cost the Russian military thousands of fighting vehicles, the Kremlin is desperate for replacement APCs. Seventy-year-old BTR-50s sometimes are the best it can do.

There’s a cost to deploying an obsolete, thinly-protected BTR, however. And that cost was evident last week as a multi-regiment Russian force made a frantic, late-season push toward Avdiivka, a free settlement in eastern Ukraine’s Donetsk Oblast, just north of Donetsk City, the seat of a pro-Russian separatist “republic.”

A BTR-50 was among the Russian losses after Ukrainian mines, artillery, drones and anti-tank teams smashed several long columns of armored vehicles attempting to flank Avdiivka from the south and north.

In a heady several days of fighting, the Russians lost scores of vehicles. It seems one BTR-50 rolled over a mine, exploded and flipped upside down. A Ukrainian drone captured the carnage as the bodies of the BTR’s occupants spilled onto the road.

Any vehicle is vulnerable to mines and other heavy anti-tank munitions. But a BTR-50 is especially vulnerable.

The BTR-50P—one of the main variants of the old vehicle—is a 15-ton, diesel-fueled armored tractor with two crew and space for up to 20 passengers. It usually packs a heavy machine gun.

The Soviet Union developed the BTR-50P in the early 1950s. It entered service in 1954 and, for the next 12 years, was the Soviet army’s mainstay fighting vehicle. BTR-50 crews would haul infantry into battle, protect the soldiers as they dismounted then support them with its machine gun.

The BTR-50P is lightly-armed and thinly-armored, however. When the heavier, and more heavily-armed, BMP-1 debuted in 1966, thousands of BTR-50Ps cascaded to second-line units.

The BTRs hauled artillery, engineers and anti-aircraft guns until MT-LB tractors began displacing the older vehicles from those roles, too. As of last year, the Russian army operated just a handful of aged BTR-50Ps plus somewhat more modern BTR-50PU command vehicles.

But as losses of newer BTRs, BMPs and MT-LBs spiked, and factories struggled to produce enough replacement vehicles, the Kremlin this spring began reactivating some of the potentially hundreds of BTR-50s that had been languishing in long-term storage.

There was some speculation that the war-reserve BTRs would fill second-line roles as command posts or artillery-support vehicles. But then careful observers spotted some of the 15-ton vehicles with 23-millimeter autocannons in place of their usual heavy machine guns.

It was apparent the Russians planned to send the up-armed APCs close to the front, either as infantry-support vehicles or crude air-defense systems.

In those roles, the geriatric BTRs were all but doomed. At least one of them blew up and flipped over in a pile of its deceased former occupants on a road outside Avdiivka.

Tragically for the BTR’s crew and passengers, the Russians’ Avdiivka offensive seems to be mostly symbolic: an effort to achieve some kind of victory in advance of the coming winter, when the cold weather and wet ground might make further advances—by either side—difficult.

As a symbol, the attack so far has failed. If the assault stands for anything, it stands for failure. The Kremlin sent troops to die in an obsolete vehicle as part of an ill-prepared force pursuing an objective with little real military value.