Unofficial Fallout 4 Patch

Cannot be fixed trivially because the ammo objects have the data for single rounds and ammo cases in a single nif file. Depending on how many items are placed, the game will automatically select the single round mesh (if only one item is placed) or the ammo case mesh (if more than one item is placed).
While the actual meshes are still separate on their own nodes, the physics data for both meshes are in a single physics data block and they are referred to by body indices. In addition, it appears that the node names of the meshes those body indices are related to must be specified somewhere withn that physics data file - because simply copying the physics block from the .308 mm ammo onto the 5.56 mm ammo mesh didn't work at all (5 mm ammo is an even better fit but has an entriely different case so I cannot use the 5mm ammo physics file).

Therefore, I see no chance to get this fixed until the physics data have been properly decoded.

Collision issues cannot be addressed.