Help to ID unknown 40mm projectiles

[retireddigger]

New guy seeking to satisfy curiosity on pair of aluminum or alloy projectile bodies, one with exposed non-ferrous rotating band showing rifling which is difficult to count lands; other in a corroded ferrous "can" with traces of rifling on presumed rotating band. Both measure at or slightly above 40mm in diameter and are 80mm in length. Unfortunately recovery site and details are unknown. Appreciate any ideas or enlightenment!

 

[Falcon]

These look like practise projectiles for the M203 40mm Under-barrel grenade launcher mounted to the M16 Rifle.

 

[EOD]

Falcon, actually these are 40x53R for the series of automatic grenade launchers, the so called 40mm high velocity (HV). The ones that are fired by hand held weapons (M203, M79 etc.) are the 40x46R low velocity (LV)
The main ID feature are the driving bands.

 

[HAZORD]

Retireddigger,

The solid projectile on the left is most likely a M385 TP projectile as detailed by EOD. During Vietnam they were fired from the automatic grenade launchers on the chin turrets of Cobra Helicopters, and other vehicle mounted applications. They have become more popular and more available in the Gulf wars. Datasheets for your bullet attached.