Soldiers from 5th Armored Brigade, First Army Division West, developed a course of instruction to counter the threat of commercial, off-the-shelf unmanned aerial surveillance vehicles at McGregor Range Complex, N.M., June 28, 2019. (DVIDS) WASHINGTON — Recent Chinese sanctions that have disrupted business for an American drone maker are a sign from Beijing that the US supply chain is still interwoven with Chinese entities — and the latest reason US defense firms should move to free themselves,