English: 3d Cavalry's commander, COL David Teeples wearing the Cavalry Stetson in Iraq. 3d Armored Cavalry Regiment's Commander in Iraq wearing the Stetson. COL David Teeples is accompanied by the 3rd Armored Cavalry Regiment (ACR) Command Sergeant Major (CSM) John R. Caldwell, the 16th CSM of the 3d ACR. CSM John Caldwell served as the 3rd ACR's CSM from 2002-2005 and Sabre Squadron's (2/3 ACR) CSM prior to being appointed the regimental command sergeant major. The well liked and respected CSM was wounded in an Improvised Explosive Device (IED) attack during the 3rd ACR's (and his) second tour in Iraq on April 17, 2005. PVT Joseph Knott died in the attack, CSM Caldwell would not return to duty.