The weapons of the Primaris Marines have been built especially for them, with improved technology and design by Belisarius Cawl.
Via our good friends at Lexicanum
The Mk.II Cawl Pattern Bolt Rifle is a new version of the venerable Boltgun developed in the closing days of the 41st Millennium for the Primaris Space Marines. Named after Magos Belisarius Cawl, the large Cawl-pattern Bolter is said to be re-crafted and re-engineered to perfection. The Bolt Rifle is a larger and longer-barreled upgrade of the standard Bolter, allowing for longer range and armour-piercing capability. The Bolt Rifle is highly modular, allowing for a number of easily-created variants such as the Auto Bolt Rifle, which is equipped with a high-capacity Magazine and the Stalker Bolt Rifle, which is essentially the Bolt Rifle equivalent of a Stalker Bolter. The Boltstorm Gauntlet is a Bolt Weapon used by the Primaris Space Marines. Often wielded by Captains, it bares a strong resemblance and function to Roboute Guilliman’s famed weapon Hand of Dominion. The Boltstorm Gauntlet consists of a Power Fist with built-in Bolter. The Hand of Dominion was a Power Fist with built-in Bolter, that was one of the many weapons owned by the Primarch Roboute Guilliman. It was an iconic weapon, that was of not only surpassing quality, but also seen by the Ultramarines Legion as a symbol of their Primarch’s might and authority.
The Redemptor Dreadnought is a newly created variation of the Space Marine Dreadnought and is designed to allow maimed Primaris Space Marines to continue to fight the Imperium’s many enemies. Taller, broader and more cleverly wrought than the traditional Dreadnought desin, these goliaths are powered by hyper-dense reactors and sophisticated fibre bundles. Such is the miraculous design of the Redemptor’s neural links that its inhabitant, despite being entombed in the sarcophagus within the Dreadnought’s chest, can exercise control with surprising dexterity and speed. It is whispered that the advanced systems of the Redemptor are a curse as well as a blessing. The Mechanicum Tech-Priests that first built these walking machines of destruction spared little thought to the health of the incumbent, seeing him as little more than another part to be interred or replaced as necessary. Many of those Redemptors that have fought for a sustained period have already had their sarcophagi replaced, their original pilots burned out by the intensity of the machine’s destructive prowess. Redemptor Dreadnoughts wield an array of devastating weaponry including a Onslaught Heavy Gatling Cannon or Macro Plasma Incinerator on its right arm and a Redemptor Fist with Heavy Flamer or Onslaught Gatling Cannon on its left. It is also equipped with 2 chest-mounted Fragstorm grenade launchers or storm bolters and a carapace-mounted Icarus Rocket Pod for air defense.
The Repulsor is a newly unleashed battle tank, used by the Primaris Space Marines. The Repulsor is recognizably of the same STC origins as the armored vehicles used by their Space Marine brethern. Like the Primaris’ weapons and power armor, the Repulsor is created in the forges of Mars; though whether its design is based on recovered ancient technology or from Archmagos Dominus Belisarius Cawl’s own mind, is unknown. The Repulsor armored transport is a deadly combination of maneuverability and brute force. Due to the turbine array at its rear, it has tremendous power, and it is held aloft by powerful anti-gravitic generators. The Repulsor is so heavily armed and armored that it does not skim over the landscape as many grav-tanks do, but instead crushes the ground below it, grinding apart any caught within its field. The tank he designed is indeed capable of traversing almost any terrain, even lava streams or lakes of boiling acid should the need arise. However, it moves little faster than the armored behemoth of the Land Raider, for its power is directed more into the manipulation of clashing gravitic energies than forward motion.
Those that attempt to close with a Repulsor find themselves fighting against a wave of energy that disorientates and batters those nearby; due to the ventral plates being powered separately, this can even be directed by the craft’s pilot to better effect. Multiple layers of ceramite and adamantium overlap to make the Repulsor’s hull all but impervious to normal weaponry; even a direct hit from a missile will likely leave little more than a scorch mark. Though its primary role is to ferry Primaris Space Marines, the Repulsor is far more than a simple transport. It mounts a staggering variety of guns. The Las-talon and pintle-mounted Onslaught Gatling Cannon in the tank’s turret blasts apart enemy vehicles that could conceivably pose a threat, whilst the extensive suite of bolt weaponry, Auto launchers, Fragstorm Grenade Launchers, Krakstorm Grenade Launchers, and Heavy Stubbers lay down a storm of horde-killing firepower.