'[HIMARS'] GPS lends them a high degree of precision that makes targeted strikes extremely effective... The range, precision, and mobility of the HIMARS has allowed Ukraine to strike at Russia’s logistics and supply lines without fear of immediate retaliation. They’re blowing up Russian ammo depots and logistical centers with impunity."
The US admits to providing real-time intelligence, satellite data, and targeting telemetry.
It's unsurprising HIMARS is performing as advertised, striking far behind front lines with pinpoint accuracy.