"What do I do?" he asked the U.S. military team member, far away at a base in southeastern Poland. "What are my options?"

Using phones and tablets to communicate in encrypted chatrooms, a rapidly growing group of U.S. and allied troops and contractors is providing real-time maintenance advice -- usually speaking through interpreters -- to Ukrainian troops on the battlefield.
[...]
The exchange is part of an expanding U.S. military help line aimed at providing repair advice to Ukrainian forces in the heat of battle. As the U.S. and other allies send more and increasingly ["]complex["] and high-tech weapons to Ukraine, demands are spiking. And since no U.S. or other NATO nations will send troops into the country [FALSE] to provide hands-on assistance -- due to worries about being drawn into a direct conflict with Russia -- they've turned to virtual chatrooms.
[...]

A key problem, said one officer, is that Ukrainian troops are pushing the weapons to their limits -- firing them at unprecedented rates and using them long after a U.S. service member would turn them in to be [either] repaired or retired scrapped...."They're using these systems in ways that we didn't necessarily anticipate," said the officer, pointing to the tablet. "We're actually learning from them by seeing how much abuse these weapon systems can take, and where's the breaking point."

The Ukrainian troops are often reluctant to send the weapons back out of the country for repairs. They'd rather do it themselves, and in nearly all cases -- U.S. officials estimated 99% of the time -- the Ukrainians do the repair and continue on.[...]

Here's every weapon US has purportedly supplied to Ukraine, a/o 26 Aug 2022, of which ...

[...]
• 155mm Howitzers
A towed field artillery piece that can hit targets up to 30 km, or 18 miles away. The U.S. has sent 126 of these howitzers, along with 806,000 155mm artillery rounds and 126 tactical vehicles to tow the howitzers

The M198 Howitzer is currently in active service with both the US Army and the Marine Corps though it is being replaced by the M777 ultra-lightweight 155mm howitzer in selected units.

• 105mm Howitzers
The U.S. committed to sending 16 105mm howitzers [towed Hawkeye, M101, or M119 series? Or self-propelled?] and 108,000 105mm artillery rounds to go with the howitzers. The U.K. has already provided the L119 model, which is a light weight howitzer that can provide direct fire support at armored vehicles or buildings or indirect fire to support combat arms in ranges over 10 km, or 6 miles.
[...]