Some US Navy High Capacity (HC) projectiles have a Dummy Steel Nose Plug (DNP, no nose fuze) with an Auxiliary Detonating Fuze (ADF) and a Base Detonating Fuze (BDF). Here’s an example I posted in an earlier thread from the Vietnam era (see projectile markings, even though it has an incorrect VT nose fuze): USN 5"/38 Caliber Questions
My question is about the function of the ADF when there is no nose fuze. In Navy documents describing the function of the ADF (such as OP 1664, US Explosive Ordnance), the description typically says that the ADF will not function without a nose fuze to initiate the detonation.
So what is the function of the ADF in an HC projectile without a nose fuze? Are some ADFs designed to detonate on impact or is it there for some other reason? Is it simply there to contain the explosive inside the projectile?