IIRC from when I worked with CENTAF, anything under 23mm was "small arms" in the daily SAFIRE report on who was shooting at our aircraft with what. this means that a 20mm or .50 cal anti aircraft weapon was small arms.
While it is more likely that AK-47 and things like a 7.62 M-60 light machine gun, or its equivalent depending upon what arms are generally in use in the area, would be to hand for the folks bearing arms down there, such small arms have sufficielt metal in them, particularly in when thrown into the air in volume, to put a serious crimp in an air assault or airevac operation.
If anyone doubts me, consider the infamouss large scale Apache deep strike during the 2003 attack into Iraq ...