PoserWorld (subscription site) has military clothing. Daz has some too. There are various weapons in the MP here. As for a particle generator, the thing that comes closest is MetaForm from WeirdJuice. Python based so it only works in Propack and P5.

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.