Under the command of Paddy O'Brien, the IRA's 2nd Cork Brigade attacked an armed convoy of the Auxiliary Division returning to their barracks in Millstreet after collecting supplies.

[11] After monitoring the route for 12 days and recording the Auxiliaries movements, the IRA noticed that the size and strength of the convoy could vary each trip, with the smallest composed of 2 Crossley tenders carrying 20 personnel and the largest consisting of 6 vehicles and 40 men.

[14] As armoured cars were beginning to see more extensive use by Crown forces, the column had been training their men throughout the Spring in the manufacturing and deployment of mines as a means of countering them.

[16] On 14 June, the IRA commanders sent messages to the brigade's other battalions in Newmarket, Kanturk, Mallow and Charleville requesting that they send all available men to the Rathcoole area.

[6] After the battalions had assembled the following day, the IRA force commanded by Paddy O'Brien numbered upwards to 140 men armed with rifles, shotguns and a Hotchkiss machine gun.

[15] The British again drove through the ambush site at about 4:30 p.m.;[15] the convoy consisted of 3 Crossley tenders with an armoured Lancia leading at the front and carried 25 personnel.

[20] When the Auxiliaries arrived back at the area on their return trip, the volunteers held off from attacking the first 3 lorries in the convoy and waited until the fourth vehicle had reached the sixth mine.

[21] They immediately began firing towards the IRA's positions with their Lewis gums, but due the terrain providing the volunteers with natural protection they failed to inflict any casualties.

[17] After recognising the precarious situation he was faced with, the commander of the convoy William Edward Crossey ordered one of his men, Francis Scott, to run back to their barracks in Millstreet and alert the rest of their company.

Despite coming under heavy gunfire during the initial part of his journey, Scott managed to reach Mount Leader House and reinforcements were immediately sent to relieve the convoy.

[24] However, this was rectified the following day when an IRA detachment sent back to the ambush site to retrieve the undetonated mines discovered 1,350 rounds of ammunition abandoned by the Auxiliaries whilst they were clearing up the area.

[17] On 24 June, about a 1,000 British troops from the towns of Macroom, Kanturk, Tralee, Ballincollig, Ballyvonaire, Buttevant and Killarney carried out large scale searches around the Rathcoole area.