I was looking at some firearms sites, and notices the modular trend that is hitting all the modern firearms. Here are so examples of firearms that are of a modular design: H&K G36, and F2000. Here are the addition that I have made, they are called the modular barrel, underbarrel mounts, and they have the following costs(note: That these are made for the FCG on Rayguns site Shadowrun and Firearms).

Modular Barrel System:[/B] This weapon comes standard with a modualr barrel making it less expensive to mount barrel and barrel-mounted accessories. Multiply final costs x0.75 per barrel-mounted accessory.

Design Cost: +75
Weight Factor: +0kg
Conceal Factor: +0
Max. Rating: NA
Space Used: Barrel

Modular Underbarrel Mounting System:[/B] This weapon comes standard with a modualr underbarrel-mount making it less expensive to mount underbarrel-mounted accessories. Multiply final costs x0.75 per underbarrel-mounted accessory.

Design Cost: +100
Weight Factor: +0kg
Conceal Factor: +0
Max. Rating: NA
Space Used: Under

Here is a sample of some weapons that I have made with the above modifications and the SOPMOD kit for them..

MWS-26AR1a
Caliber: 7.62mm NATO
Range: AR
Conceal: 3
Ammo: 30c
Mode: SA/FA
Damage: 9S
Weight: 4.59
Availability: 6/2day
Cost: 1650
SI: 2
*MWS-26AR1a-1b come standard with modular barrel and underbarrel mount, making it less expensive to mount barrel and underbarrel mounted accessories, multiply final cost x.75 per barrel and underbarrel accessories.
*MWS-26C1a-1b accepts the MWS-26 SOPMOD Kit.

MWS-26AR1b
Caliber: 7.62mm NATO Caseless
Range: AR
Conceal: 3
Ammo: 36c
Mode: SA/FA
Damage: 9S
Weight: 3.67
Availability: 7/2day
Cost: 1750
SI: 2
*MWS-26AR1a-1b come standard with modular barrel and underbarrel mount, making it less expensive to mount barrel and underbarrel mounted accessories, multiply final cost x.75 per barrel and underbarrel accessories.
*Stock and egronomic pistol grip provide 1 point of recoil compensation each.
*MWS-26AR1b usess caseless 7.62mm NATO ammunition
*MWS-26C1a-1b accepts the MWS-26 SOPMOD Kit.

MWS-26C1a
Caliber: 7.62mm
Range: Carbine
Conceal: 4(5)
Ammo: 30c
Mode: SA/FA
Damage: 8S
Weight: 2.6
Availability: 6/2day
Cost: 1625
SI: 2
*MWS-26C1a-1b come standard with modular barrel and underbarrel mount, making it less expensive to mount barrel and underbarrel mounted accessories, multiply final cost x.75 per barrel and underbarrel accessories.
*Stock and egronomic pistol grip provide 1 point of recoil compensation each.
*Retractable stocks provide a +1 Conceal Rating when retracted.

MWS-26C1b
Caliber: 7.62mm caseless
Range: Carbine
Conceal: 4(5)
Ammo: 36c
Mode: SA/FA
Damage: 8S
Weight: 2.08
Availability: 7/2day
Cost: 1725
SI: 2
*MWS-26C1a-1b come standard with modular barrel and underbarrel mount, making it less expensive to mount barrel and underbarrel mounted accessories, multiply final cost x.75 per barrel and underbarrel accessories.
*Stock and egronomic pistol grip provide 1 point of recoil compensation each.
*Retractable stocks provide a +1 Conceal Rating when retracted.
*MWS-26C1b uses caseless .308 ammunition.
*MWS-26C1a-1b accepts the MWS-26 SOPMOD Kit.

SOPMOD Kit: +3855
You can either purchase the entire kit or individual accessories. (Note: Modular Barrel and Underbarrel does not apply to this kit or individual accessories)

ACOG Reflex: +300
Reflex Sight provides a -1 target number modifier when used.

ACOG 4X StarVision Scope: +600
Count as rating one scope with low-light vision enhancement.

AN/PEQ-20 IR Pointer/Illuminator: +400
Count as Laser Designator.

ADVAT.328-compliant smartlink 1: +375
Counts as an internal smartlink I system with range finder or grenade link.

ADVAT.328-compliant smartlink 2: +450
Counts as an internal smartlink II system with range finder or grenade link.

Visible Laser: +250
Laser Sight provides a -1 target number modifier when used. +50 to upgrade to hight powered Laser Sight.

Visiable Light (9 volt): +50
Provides no bonuses.

Foreward Grip: +50
Foreward Grip provides 1 point of recoil compensation when used.

QD Sound Suppressor: +525
Takes one simple action to attach or remove. See Shadowrun and Firearms for Advance Sound Suppression Rules, or use standard suppression rules.

QD TS-20 MGL: +605
Takes one simple action to attach or remove.

TS-20 MGL
Caliber: 20mm Grenade
Range: GL
Conceal: -2
Ammo: 8m
Mode: SS
Damage: as grenade
Weight: +2
Availability: +4/x2
Cost: +605
SI: +1

QD TS-12 SG: +250
Takes one simple action to attach or remove.

TS-12 SG
Caliber: 12Guage
Range: SG
Conceal: -2
Ammo: 5m
Mode: SA
Damage: 10S
Weight: +1.5
Availability: +2/x1.5
Cost: +250
SI: +.5