The Kilocredit Challenge

Since the meta seems to be slowly leaning back towards micromissiles, I challenge you to craft a potent missile, capable of slaughtering an enemy Gunship with a single salvo consisting of not more than 20 missiles, the entire salvo costing not more than one kilocredit, and massing not more than one metric ton.

The rules are as follows :
1. No drones are accepted, but missiles may mount blast launchers for dispersing flak. Nothing even remotely resembling a gun or laser is allowed.
2. You are allowed to fire exactly one salvo of missiles, that salvo consisting of not more than twenty missiles.
3. The entire salvo must cost less than one kilocredit, and mass less than one Megagram.
4. No boosts are allowed. The missiles must reach their targets exclusively under their own power.
5. The target is one stock Gunship, with the AI set to Defensive.
6. The missile must successfully disable the Gunship thrice in three encounters.

Scoring will be as follows :
Total score = [{1000-(Mass of the entire salvo in kilograms)} + {1000-(Cost of the entire salvo in credits)}] / (Number of missiles in the salvo)
In the case of a tie, the missile with the lowest cost will be ranked higher.

Difficult Mode (x2 Multiplier) :
1. The salvo can contain, at most, only ten missiles.
2. The entire salvo must cost less than five hundred credits, and mass no more than one hundred kilograms.
3. No mods are allowed, be they edits to limits.txt or modded materials.

Extreme Mode (x5 Multiplier) :
1. At most, only ten missiles may be used, distributed over a maximum of two salvos.
2. The entire salvo must cost less than five hundred credits, and mass no more than one hundred kilograms.
3. No mods are allowed, be they edits to limits.txt or modded materials.
4. Nuclear Thermal Rockets and Fluorine Combustion Rockets are banned.
5. The targets are two stock Laser Frigates, with the AI set to Defensive.
6. The missile must successfully disable the Laser Frigates thrice in three encounters.

Good luck!

Leaderboard (Unmodded Entries) :
1. RiftandRend (Jezzail Micro-missile) : 3699.4 (Difficult)
2. RiftandRend (Fimir 2 Micro-Missile) : 1814.2 (Difficult)
3. SevenOfCarina ([PDV] Switchblade) : 765.8 (Difficult)
4. RiftandRend (Iris 2 Micro-Missile) : 702.5 (Extreme)
5. RiftandRend (Iris Micro-Missile) : 666.5 (Extreme)
6. RiftandRend (Fimir Micro-Missile) : 601.2 (Difficult)
7. Fgdfgfthgr (The Sharp Missile) : 491.63 (Difficult)
8. tukuro (The Hunter Missile) : 155.8 (Normal)
9. Rorie  (Mini Micro Missile) : 78.94 (Normal)

Leaderboard (Modded Entries) :
1. The Astronomer (Tiny Kinetic Missile 2 v1.1) : 172.13 (Normal)
2. The Astronomer  (Missile [RHM] K Tiny) : 161.57 (Normal)
3. The Astronomer (Tiny Kinetic Missile v1.2) : 111.09 (Normal)

"There was an attempt." :
1. cyborgleopard (Brigandine Micromissile) : -16.3 (Normal)