Veteran Squad
Though the term Veteran Squad can refer to any number of groups of experienced soldiers gathered in a single unit, in the context of Warhammer 40k this almost always means either the Hardened Veteran squads of the Imperial Guard (Read: actually survived a battle) or, more frequently, the squads consisting of the most experienced brothers of a Chapter of Space Marines.
Consisting exclusively of members of the Chapter's First Company, Veteran Squads consist of three different kinds of Battle Brothers: the Terminators, the Sternguard Veterans and the Vanguard Veterans. Though these groups maintain a sense of rivalry with one another, on the battlefield they are a lethal and efficient force.
Sternguard Veterans
The Sternguard are Tactical Marines cranked up to 11. They are the masters of the Bolter in all of its forms (In fluff, in the Crunch they have the exact same Ballistic Skill): from a standard Bolter to the Storm Bolter to various kinds of Combi-weapons all the way up to the Heavy Bolter. They are also trained in the light support weapons used by Tactical Marines: the Flamer, the Plasma Gun, the Meltagun and the Gravgun. They are also one of the few squad types entrusted with Heavy Flamers.
Aside from the standard issue Bolt round the Sternguard Veterans are equipped with a number of different and specialized Bolter rounds:
- Dragonfire Bolts are designed to explode into a superheated gas to tell any form of cover the enemy is in to go fuck itself.
- Hellfire Bolts replace the projectile's explosive payload with mutagenic acid, designed to combat the Tyranids and all sorts of big non-vehicle targets.
- Kraken Pattern Penetrator Bolts are improved rounds with a better range and penetration.
- Vengeance Bolts are more or less miniature plasma grenades that violently explode upon impact, but are a danger to the user as well. These were designed to combat the Chaos Space Marines.
Vanguard Veterans
The Vanguard are the big brothers of the Assault Marines. Highly skilled in close-quarter fighting, they use their Jump Packs and powerful weaponry to make short work of the enemy.
Though the standard equipment of the Vanguard are the Bolt Pistol and Chainsword, they have access to the Chapter's armory to become even deadlier in combat. The most commonly used equipment for the squad consists of twin Lightning Claws and the Thunder Hammer/Storm Shield combination, depending on what the mission calls for. They are also equipped with a selection of grenades.
Their "Heroic Intervention" rule used to let them assault out of deep strike, but needed to be declared they were going to try before placing and rolling for scatter. This has been changed so that they ignore disordered charges, and their sarge auto passes the test for a Glorious intervention.
In 7th, they still ignore disordered charges, but no more auto-pass Glorious Intervention tests: they can now re-roll dice for charge. Which, if you have Jump Packs, is pointless, as you can already re-roll charge. (Which is why you use the jump packs in the MOVEMENT phase.)
Tyrannic War Veterans
After the Battle for Macragge, the Ultramarines formed the Tyrannic War Veterans from the survivors of the battle Companies. Trained by Ortan Cassius, their sole mission is to exterminate all Tyranids. They are more or less Sternguard with a bit of Deathwatch-light training thrown in to kill Tyranids as quickly as possible.
Tyrannic War Veterans "are" actually part of the first company, though they take their orders directly from Chaplain Cassius. They are a select group of Veterans from all companies that survived the Tyrannic Wars, but since they act as a separate unit from the rest of the chapter's organisation this meant a bit of deliberation over the Codex Astartes on the part of Marneus Calgar before they could be deployed. They all carry relics of the fallen first company, wearing armour pieced together from the previous 1st company veterans, and carrying their old bolters which they load with Hellfire shells.
They also don't recruit new members, and number only a few dozen, which will inevitably decrease over time and be replaced with "standard" 1st company veterans.
Also, with the Tyranids Codex being the shitfest it is, the powers that be decided to drop in a Dataslate for the Tyrannic War Veterans, being a special formation whose existence is akin to kicking a dying puppy.
Company Veterans
Since all of the Dark Angel's first company veterans who would normally make up the Vanguard or Sternguard units only deploy in terminator armor they don't get either. Instead they get "Company Veterans Squad". Literally veterans of whatever company they're in rather than the first. While not singularly specialized for ranged or melee like Sternguard/Vanguard, lacking specialist ammo for shooting, and jump packs for assaulting, they have the option to mix and match melee and ranged into the same unit, giving them some good versatility. They're also cheaper, as compensation for not having Special Bolter Rounds.
Command Squads have been axed in 8th and rolled into Company Veterans. Inculding the ability to take Bikes for a cost, while Champions and Apothecaries are taken separately. Dark Angels can upgrade to Combat Shields without having to give up one of their weapons. Making them the best choice for Green Wing armies, or can be meats shields for the Imperial Space Marine. With the buffs to Plasma weapons and Combi-guns, its not like DA players weren't already taking them for more Plasma spam. Admit it, you were already guilty of this or considered doing so.