I remember you mentioned the idea about possibly trying to make a few of these when the armors were further along, so I thought maybe I could just put the reference links here for easy access later on?

MA5D Assault Rifle http://halo.wikia.com/wiki/MA5D_Individual_Combat_Weapon_System
- Magazine Size: 32 in H4, 36 in H5
- Range: Short to Medium
- Accuracy: Good in close range, still accurate at medium range with controlled bursts.
- Weight: 7.1 kg

MA37 Assault Rifle http://halo.wikia.com/wiki/MA37_Individual_Combat_Weapon_System
- Magazine Size: 32
- Range: Short to Medium
- Accuracy: Fairly accurate in short controlled bursts
- Weight: 6.9-7kg? (it looked a little lighter than the MA5's at least)

M739 Light Machine Gun http://halo.wikia.com/wiki/M739_Light_Machine_Gun
- Magazine Size: 64 to 128 rounds per mag, 72 standard
- Range: Medium to close range
- Accuracy: Medium
- Weight: 9.6kg

BR85HB SR Battle Rifle http://halo.wikia.com/wiki/BR85HB_SR_Battle_Rifle
- Magazine Size: 36 rounds per mag
- Fire Mode: 3-round burst (would be cool if this is possible in SE)
- Accuracy: High
- Range: Medium to long
- Weight: 7.6kg
(Would really like to see this one first out of the set, one of my favorites from what I have seen.)

M90 CAWS Shotgun http://halo.wikia.com/wiki/M90_Close_Assault_Weapon_System
- Magazine Size: 6-8 shells
- Range: Short to medium range
- Accuracy: Low to medium based on target range
- Weight: 5.4-5.8kg (empty and loaded)

M7C SMG http://halo.wikia.com/wiki/M7/Caseless_Submachine_Gun
- Magazine Size: 60 rounds per mag
- Accuracy: Low to medium
- Range: Short to medium
- Weight: 1.3kg - 2.88kg

ARC-920 Railgun http://halo.wikia.com/wiki/Asymmetric_Recoilless_Carbine-920
- Magazine Size: 1 slug (but implied to hold more in the latest games, so maybe 4-5?)
- Accuracy: high
- Range: Low to medium (though I think it could be usable for long range)
- Weight: 14.9kg

M6D Magnum http://halo.wikia.com/wiki/M6D_Personal_Defense_Weapon_System
- Magazine Size: 12 rounds per mag
- Accuracy: High
- Range: Short to medium
- Weight: NA, but likely less than 1.3kg

SRS99 Sniper Rifle http://halo.wikia.com/wiki/Sniper_Rifle_System_99-Series_5_Anti-Mat%C3%A9riel
- Magazine Size: 4 rounds per mag
- Accuracy: High
- Range: Long
- Weight: 15.6kg

M41 SSR MAV/AW http://halo.wikia.com/wiki/M41_Surface-to-Surface_Rocket_Medium_Anti-Vehicle/Assault_Weapon
- Magazine Size: 2 rockets (so 2 per "rocket" assembled would work here)
- Accuracy: High
- Range: Short to long
- Weight: Guessing around from 12-15kg?