My suggestion for an ammo economy revision is focused around ammo pickup values and designed to emphasise the role of kinetic weapons as primary weapons, as I believe that Kinetic and Energy weapons should have more distinct roles; Kinetic weapons as primary weapons, and Energy weapons as secondary weapons.
The idea is that Kinetic ammo is readily available, but provided in smaller quantities per brick.
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All AI enemies have a 100% chance to drop a Kinetic ammo brick when killed
Screen no longer flashes when collecting a Kinetic ammo brick
Shielded AI enemies have a 100% chance to drop an Energy ammo brick when killed
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The changes in ammo pickup values listed below apply only to Kinetic weapons.
Ammo pickup values for Energy and Power weapons remain unchanged.
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Submachine Guns: 12 ammo per brick
Auto Rifles: 10 ammo per brick
Sidearms (fully automatic): 10 ammo per brick
Pulse Rifles: 9 ammo per brick
'Crimson' Hand Cannon: 9 ammo per brick
Sidearms (burst fire): 9 ammo per brick
Sidearms (semi automatic): 8 ammo per brick
Scout Rifles: 6 ammo per brick
Hand Cannons (excluding 'Crimson'): 4 ammo per brick
Bows: 3 ammo per brick
Shotguns: 2 ammo per brick
Sniper Rifles: 2 ammo per brick