So ive never found anything that was genuinely impossible to retexture, but everything mentioned here definitely does not work with the usual methods. I havent tried toe SSG82 yet, but every other gun mentioned needs a couple annoying workarounds to get a new texture, it would be so much easier and a better end result if all models came with a hiddenselection that allowed full modification of the displayed texture (and by extension, the .rvmat). The P1 stands out as a notable exception as being the most uniquely resistant to new textures, its difficult to get the colors you want on it, though pretty easy to make it either all pink or all cyan, im just trying to get camo patterns on it starting with snow. This is my best result so far and proof that its possible to do without modifying the .p3d or model.cfg.