If you're running Suros with focused fire, then you should choose lightweight instead of hammer forged!
With focused fire and linear compensator/field choke you are already so close to the auto-rifle range cap that hammer forged gives you less then half of its already small bonus as it will hit the cap. Because of this, lightweight is the better option as it gives you a good boost to movement speed, strafing speed, and jump height.
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Serious question -- Hammer Forged says increased range and accuracy. Has for either a long time or since forever. But some unofficial sites I visit don't mention an aim-assist buff, just the x% buff to range. I thought they only somewhat recently did the whole range -> aim assist effectiveness thing.