Arsenal mod has a large selection of weaponry. Some will only be available once as a reward and others will only be found on certain npc's making it so you'll always be finding unique weapons. It adds over 50 new weapons all with there own animations as well as making the vanilla weapons non-mirrored.
Not the weapon above but it explains just how badly the Stalker devs nerfed the Abakan. I think the in game example needs work doing on it so that it is more realistic.