In 1943, experimentation began in Great Britain, Canada, and Australia into developing a shortened and lightened version of the Lee Enfield rifle. In Australia, the work was done on the No1 Mk3* rifle, as the Lithgow Arsenal had never switched over to production of the No4 rifle.

We have three experimental prototype carbines from Lithgow to look at today. The first is simply a shortened SMLE, with no serious effort given to reducing weight. This rifle is visually very similar to the commercial SMLE "Jungle Carbines" marketed by a number of companies, although the real one here has several features missing form the commercial copies - most notably a simple rear aperture sight.

The other two are examples of the two types of rifle that were ultimately considered for formal adoption (and a large order for one was actually placed, before being cancelled at the end of WW2). These are designated the No6 Mk1 (with a rear aperture sight) and the No6 Mk1/1 (with a rear tangent sight). Approximately 100 of each were made, half with brass buttplates and half with rubber recoil pads. In this form, slightly more than a pound was removed from the standard SMLE, and the reduced length did make for a handier rifle. The Australian need for this type of carbine was removed with the end of the war, although in Great Britain the No5 Mk1 carbine - the same in practical terms as these Australian examples - would be taken into formal service for several years.