To address this a 25 pounder (87.6 mm, 3.45 in) gun-howitzer was fitted to a turret on the second prototype Australian cruiser tank hull and successfully test fired on 29 June 1942.

[8] New South Wales Government Railways' production line at Chullora work had started on assembling the first 25 AC3 tanks for trials when the programme was terminated in July 1943.

[9][10][Note 2] The 65 tanks that were not required to serve as a physical record in war museums in Australia and the UK were sold off by the Commonwealth Disposals Commission.

[9] One of the three saved was the only completed AC3 (serial number 8066) which is now located at the Treloar Resource Centre at the Australian War Memorial in Canberra.

[11] An AC3 mockup was assembled from unused AC3 armour castings and a mix of AC3 and AC1 parts at the Melbourne Tank Museum in 1996–97, this piece was sold to a private collector in 2006.