Who will win in Ukraine? It could hinge on which side can secure enough artillery ammunition

The war in Ukraine has turned into a lethal artillery duel and whichever side can produce the most ammunition for the big guns on the battlefield could have the edge in the conflict, U.S. officials and military analysts say.

In its scramble for firepower, Russia is using ammunition that is half a century old and dismantling breast pumps and kitchen appliances to get microchips it needs for tanks and precision-guided weapons.

Ukraine, for its part, is relying on the United States and other NATO allies to keep up the flow of arms and ammunition, but those stockpiles have been stretched 10 months into the war.

Both militaries are burning through thousands of artillery rounds a day and are facing challenges to secure more supplies to keep up the fight. The struggle for ammunition pits Russia's defense industry — largely isolated by Western sanctions — against Ukraine's war-damaged economy and its supporters in NATO.

To fuel its war effort, Russia is now drawing on stockpiles of 40- to 50-year-old ammunition, including 152 mm artillery rounds that are in short supply, four current U.S. officials and one former official said.

In the roughly 300 days since Russia invaded Ukraine, Moscow's forces have run through stockpiles that took more than a decade to build, two of the officials said.

The former official said Russia has been reduced to using less sophisticated "stupid bombs," and short of resorting to nuclear weapons is nearly depleted of capabilities.

It remains unclear exactly how many artillery rounds and other ammunition Russia has left in its stockpiles, and how quickly its defense industry can churn out new ammunition. Top U.S. intelligence officials repeatedly have asserted that Russian forces are using up ammunition faster than it can be produced, but have not offered estimates about Ukraine's supplies.

Military experts disagree on when Russia might run out of ammunition, with estimates ranging from a few months to more than a year.

Russia's "defense industrial base is still intact. It's under a lot of strain from sanctions, but it's still intact," said Dara Massicot, a senior policy researcher at the Rand Corp. think tank.

"Russia is trying to grab hold of the reins of their defense industry right now and make it produce more."

Russian factories are increasing production, moving to multiple shifts and bringing additional capacity online, said Paul Schwartz, a research scientist focusing on Russia's military at the Center for Naval Analyses think tank.

But it will be difficult to produce ammunition at levels sufficient to keep up with how much is being used on the battlefield, he said. U.S. defense officials said last month that Russia is burning through a staggering 20,000 rounds a day, and Ukraine about 4,000 to 7,000 a day.

"It’ll be a challenge for them," Schwartz said. "I would rather be in Ukraine's position with the full backing of the NATO alliance."

Unlike more advanced weapons, artillery ammunition requires no sophisticated electronics that are subject to Western sanctions. But Russia's machine industry has declined over the years, and it's not clear if major increases in production would require more efficient, higher quality machinery from outside the country, according to Schwartz.

Military experts said securing enough explosive accelerant to fill the artillery shells could also present a potential bottleneck for ambitious production plans.

It's an open question how the contest over ammunition production will play out, Massicot and other experts said.

"This is now a clash of sustainment and sustainment systems," she said. "How much longer can Ukraine's supporters dig deep, and keep supporting at current levels? And then on the Russian side, how well can their defense industrial base really perform?"

When Russian forces invaded Feb. 24, Ukraine found itself in a vulnerable position when it came to artillery ammunition supplies, due to a damaging sabotage campaign over several years.

From 2014 to 2018, six explosions destroyed more than 210,00 tons of ammunition in Ukraine, including crucial 152 mm shells and rockets, according to a study for the Royal United Services Institute in London.

"That was a major constraint on Ukraine's capability," said Nick Reynolds, one of the authors of the report and a research analyst for land warfare at the institute.

Ukraine is able to produce a portion of its artillery ammunition for Russian-origin howitzers, though Russian attacks on the country's power grid and infrastructure have hampered its industry. Ukraine has to rely on its foreign partners for shells that fit the new artillery pieces provided by NATO members, the experts said, and Eastern European neighbors have scoured their warehouses for Soviet-era shells.

Keeping up the flow of arms and ammunition to Ukraine has stretched NATO member stockpiles, prompting calls for a major increase in ammunition production among Western defense companies.

Industry executives, however, say it will take time to ramp up production to a wartime tempo for conventional weapons that were seen until recently as largely irrelevant for future wars.

Given the amount of time needed to prepare for such a major change in course, Reynolds said, it took too long for NATO governments and defense firms to make plans for increasing production.

"Those conversations do seem to be happening. But they are happening very slowly. They needed to happen very quickly after the war started," he said.

Secretary of the Army Christine Wormuth said this month that the American defense industry will expand artillery ammunition production from 14,000 155 mm shells a month to 20,000 by the spring and 40,000 by 2025.

Last week, the White House announced another $275 million in military aid to Ukraine, including ammunition. The U.S. already has provided more than a million rounds of artillery ammunition. The Biden administration has proposed a $37.7 billion spending bill for Ukraine that it hopes will win approval in the current lame-duck Congress. Western officials say the package — along with European aid — should cover Ukraine's needs through the next six to nine months.

Ukraine also continues to ask for more advanced and longer-range systems, including ATACM long-range missiles, F-16 fighter jets and Abrams tanks. While the administration has not decided to provide any of these systems, U.S. officials say they have not ruled out providing these or other similar weapons in the future if they conclude that Ukraine needs them for the current fight.

Colin Kahl, undersecretary of defense for policy, acknowledged recently that the massive flow of weapons and ammunition to Ukraine has strained U.S. and allied supplies.

"There's no question that it's put pressure on our own stockpiles," he said at a virtual meeting of George Washington University's Project for Media and National Security. "It's put pressure on our own industrial base. That's been true of our allies."

The vast amount of weapons and ammunition expended in Ukraine has prompted Pentagon leaders to re-examine America's contingency plans and stockpiles in the case of future conflicts, and to consider whether "we’ve done the right math," Gen. Mark Milley, chairman of the Joint Chiefs of Staff, said at The Wall Street Journal's CEO Council Summit in Washington last week. Concerned that the U.S. has "vastly underestimated the amount of ammunition" it has stockpiled for the next war, Milley directed the Joint Staff to review whether the country is ready to face conflicts in more than one area at a time, according to a senior U.S. military official.

Dan De Luce is a reporter for the NBC News Investigative Unit.

Courtney Kube is a correspondent covering national security and the military for the NBC News Investigative Unit.

Carol E. Lee is an NBC News correspondent.