Direct proof of use
Amnesty International's 2015 report on the arming of Islamic State, drawing on Armament Research Services analysis and Conflict Armament Research field work, identifies the modern Russian AK-74M among AK-family rifles in evidence with Islamic State forces in Iraq and Syria. The same report states that the AK-74M examples were most probably looted from Syrian army stocks.
Bellingcat's February 2015 open-source article on Syrian AK-74Ms separately described Islamic State as the largest AK-74M operator among non-state groups fighting in Syria and noted that AK-74Ms had also reached Islamic State fighters in Iraq. Together, the sources support Islamic State fielding of AK-74-family rifles in the Iraq-Syria campaign, but they do not provide a complete count, serial-number chain, or single dated firing incident for each rifle.
Sources: Taking Stock PDF, Bellingcat Syria AK-74Ms, Weapons of the Islamic State
Timeline
Conflict Armament Research's September 2014 dispatch documented weapons and ammunition captured from Islamic State forces in Iraq and Syria between mid-June and early August 2014. That dispatch did not identify the AK-74M by name, but it supplied part of the field-research context for later reporting on Islamic State small arms.
By February 2015, Bellingcat was reporting AK-74M distribution to Syrian Arab Army and Republican Guard units fighting Islamic State around Deir ez-Zor, while also identifying Islamic State fighters in Syria and Iraq with AK-74M rifles. In December 2015, Amnesty published the clearest catalogued AK-74M identification, listing the rifle in a baseline assessment of conventional arms positively identified in Islamic State service during the ongoing Iraq-Syria conflict.
Sources: CAR Islamic State Weapons Dispatch, Bellingcat Syria AK-74Ms, Taking Stock PDF
Battlefield role
The supported role is captured or diverted infantry small arms in Islamic State service. Amnesty describes AK-family automatic rifles as the group's main rifle type and places the AK-74M inside that small-arms pool; Bellingcat describes AK-74Ms with Islamic State fighters in both Syria and Iraq.
The sources separate possession and fielding from a proven supply route. Amnesty assessed a probable Syrian army stock origin for the AK-74M examples, while CAR's broader 2017 investigation found that Islamic State forces relied heavily on weapons and ammunition recovered in Iraq and Syria between 2014 and 2017. The record therefore treats the AK-74 entry as Islamic State use of AK-74-family rifles, centered on the AK-74M variant, not as proof of a formal transfer to the group.
Sources: Taking Stock PDF, Bellingcat Syria AK-74Ms, Weapons of the Islamic State