The oiler is designed to hold the end of the carbine sling in the buttstock while the other end attaches to the barrel band.
Reproduction
The M1 Carbine Oiler is an essential accessory used to attach a sling to your M1 Carbine rifle. M1 Carbine .30 oiler stores gun oil with Lubricator dip stick. Steel Construction, great for any gun cleaning kit. This is a new production M1 Carbine Oiler. Works with all USGI M1 carbine rifles M1A2, M1A3, M2, M2A2 & Auto-Ordnance M1 Carbine AOM150, Universal M1 Carbine and more.