I'm noticing this as well with a few items. Oil barrel being the primary one I am having trouble locating. Did not have trouble in EXP. Batteries and fresh fruit (Any fruit for that matter) is another that I am now realizing.
Batteries should be more common as they are used in multiple devices, but I almost want to say I haven't seen them spawn at all lately.
Personal comment:
Oil drums should spawn much more commonly, especially in farm land etc. Metal drums like those can be common in farm usage.
Either way, the UMP will be coming with the next stable and the VSS was put on hold for whatever reason.
Will we ever get an official statement on the m4 mistery? :P