A list of weapon manufacturers and what they do, by faction
Shi Grand Army: MAG tech and high level Esstech. Not easily accessible and expensive materials but extremely powerful.
Seburo: Sustained accuracy during high fire rates. Sacrifice damage output. Light armor.
Arakawa: Maximize damage. Magazine capacity and fire rate may suffer. Heavy armor.
Ishikawa: Accuracy and recoil control, balanced guns that don't overwhelmingly focus on one field. Stealth armor.
Nishimura: Specialized weapons. Quest rewards.
Kawakami: Wonder projects of ridiculous design and questionable usefulness. More mad science than warfare.
Imperial: Simple materials and construction, accessible but still holds late game secrets.
Krupp Works: Lasers. From laser pistols to tank cannons.
Edmund Ordnance: A range of ballistic weapons and equipment for the average soldier made from superior materials, mostly compatible with 21st century equivalents.
Golem Arms: Heavy equipment, power armor, nasty surprises. Expect explosives embedded in rifles, integrated underbarrels, high durability equipment.
Chemical Warfare Corps: Handles Esstech and anti-mage warfare, many unconvential weapons that spray acid, fire or essence plasma.
Arbiter Secrets: Top of the line Esstech, a variety of weapons and equipment that use every scrap of knowledge and advanced material the Imperials can produce with mages.
expect later Imperial designs to incorporate EssTech
Rebel Tech: Old designs from before the 2068 rebellion to the wasteland wars of the 2140s. No blueprints required, reinventing is easy, but this reflects the quality.
Wastelander: Rugged and durable designs made for simplicity and constructed from wood with imperial parts. No one consistent standard of quality.
Red Devil: Dedicated anti-Imperial weapons, incorporating grenade launchers and rockets in addition to rudimentary optics, attachments, energy weapons, etc.
Rotter: Chemical, biological, nuclear, and electric weapons. Inflict horrible things upon enemies.
Old Earth: Literally anything that exists IRL.