Railers fire extremely quickly compared to ordinary Sniper Rifles. The projectiles they fire bounce off surfaces and pierce enemies. They consume 2 ammo per shot.
Railers have greater base damage than equivalent-level Sniper Rifles but do not have a bonus to critical hit damage, inflicting roughly half the damage on critical hit compared to a same-brand purple-rarity sniper rifle for double the ammo cost. Characters specializing in dealing critical hits will find conventional Snipers to be more effective and ammo-efficient.
Zer0's B0re skill does not affect this weapon because it already penetrates enemies, overriding the ability to trigger B0re.
Maliwan - Higher elemental effect chance. Impacts cause a small splash effect.
Dahl - Burst fire while zoomed.
The Railer is a direct reference to railguns, weapons that use immense electric currents and the magnetic fields they generate to accelerate conductive projectiles (or sabots containing non-conductive projectiles) to incredible speeds.