Let's face it, the standard GTA5 weapons (and the offered Mods) are... boring.
Now, I am looking for a more... well... how to put it... a more less boring version of the weapons.
As idea, let me take you to my very good friend Peterku's page on Deviant Art, and offer you an idea of what I am talking about: https://www.deviantart.com/newest/?section=&global=1&q=Peterku
PS: do maximize each picture... his work is just... awesome... detailed... hot... and DEADLY!
They're boring, because it's 2013, the world has not reached the point where the arsenal consists of Halo-type guns.
If you want different, try looking at weapons from Metal Gear Solid 4.
@Sammy1970 Better than to use the same archetype like in those weapons designs, is, new ways/technologies to eliminate enemies, not the typical projectile (that is the real bored weaponry system in any game). Latest Call of Duty games, Warframe, MGS V : TPP, and others offers a different arsenal. Exists some projects for GTA V developing massive DLC mod to add new weapons and experiences to the game, and probably they will to appear in few months (at least, that is the info about my DLC mod with features like this included).