Basic Guns Mod for Minecraft 1.6.4/1.6.2/1.5.2

Steel Rods Pistol Grip
Stock Bolt Action
Semi-Auto Action   Automatic Action

Pump Action Iron Sights
RPG Barrel    RPG Trigger
RPG Stock    Acog Scope

Red-Dot Sight Rifle Scope
RPG Stock?    Ballistic Scope
Silencer Heavy Barrel

Foregrip    Kevlar
Pistol Rounds    SMG Rounds
LMG Rounds Assault Rifle Rounds    Shotgun Shells are the same as Assault Rounds
but with gravel on top (Crafts 8)

Sniper Rounds Silencer?
Grenade   Rocket
Unrefined Steel > Steel Ingot    Unrefined Steel Crafted with 1 iron ore and 1 coal (shapeless)

Barrel Segments Short Barrel
Long Barrel

Pistol   SMG
Shotgun

Heavy Barrel    LMG
Assault Rifle Sniper

Kevlar Helmet Kevlar Vest
Kevlar Pants    Kevlar Boots

All the guns with attachments. As i said before you get one chance to put on all the attachments you want so have them all ready when you craft them the first time.