It's not that hard to make the prop into a figure, for something like a cocking lever on a Winchester. I've done it for several gadgets. Poser will tolerate quite a few misalignments between the boning and the components in the mesh, but it's better to get into the habit of making good alignments. If you use point-at (which lets you build an hydraulic piston) the bone axis really needs to be parallel to the mesh structure. If it's an existing prop, it's worth checking to see if there are specific materials for the moving parts, as that can make the grouping much easier. (I think I shall go and try this with one of Questor's freebie Winchesters from Daz.).