ZWQ S200 Fire Rat & Viper Mod Guide
The ZWQ S200 is one internal sidearm platform sold as two distinct shell trims: the Fire Rat and the newer S200S Viper. Both use the same general mechanism, but their magazines and dart gates are not interchangeable, so the trim you own decides which parts fit.
Stock performance / design: The Fire Rat ships with its stock spring fitted and a 1.6 upgrade spring in the box and is listed around 110 FPS with Worker Gen 3 darts. The Viper also ships with a 1.6 spring, listed around 90-95 FPS on its stock spring and and around 170+ FPS once the included 1.6 spring is installed (QWK EPP darts are what the listing pairs with that figure), and adds a threaded dart gate, front-ported slide and RMR-ready optics cut over the Fire Rat.
Available Monkee Mods parts for this platform
| Part | Fits | Why you'd want it |
|---|---|---|
| ZWQ S200 Fire Rat Magazine | Fire Rat only | Spare magazine; newer batches use a weighted metal base. |
| ZWQ S200S Viper Magazine | Viper only | Spare magazine for the Viper; explicitly not compatible with Fire Rat magazines. |
| ZWQ S200 Slide Catch Spring | Fire Rat | A small, cheap service part worth keeping on hand for the slide catch. |
| ZWQ S200 Trigger Spring | Fire Rat | Replacement trigger spring; a service part rather than an output upgrade. |
| ZWQ S200 Metal Piston | Fire Rat | A smaller, ported version of the S100 metal piston; O-rings are sold separately. |
| ZWQ S200 Metal Pusher Rod | S200 (listing names the S200; Viper fitment not stated) | Two-piece metal rod and holding block with a pre-installed O-ring and spare screws. |
| ZWQ S200 Metal Magazine Release | Fire Rat | CNC aluminium, knurled magazine release for a more positive reload. |
| ZWQ S200 Metal Front Piece | S200 (listing names the S200; Viper fitment not stated) | Metal front end with a fibre-optic mounting hole; pairs with the metal priming block set. |
| ZWQ S200S Viper Dart Gate Replacement | Viper only | Adds the threaded barrel-slot dart gate used on the Viper. |
| ZWQ S200/S FireRat/Viper Holster | Both trims | The one holster confirmed to fit both the Fire Rat and the Viper. |
Recommended mods & why
- Identify your trim before ordering a magazine or dart gate. Fire Rat and Viper magazines are explicitly not cross-compatible, and the threaded dart gate above is Viper-only.
- Use the metal pusher rod and front piece as platform-wide upgrades. These are the two parts documented as fitting the S200 generally rather than one specific trim.
- Treat the springs each blaster ships with as the starting point, not the ceiling. Both trims include a 1.6 upgrade spring in the box — the Fire Rat’s fitted baseline is ~110 FPS and the Viper’s is 90–95 FPS on its stock 1.4 spring, so the 1.6 is a free upgrade, not something to buy again, not a separate upgrade to buy again.
- Share the holster across both trims. It's the one accessory documented to work regardless of which S200 you're carrying.
Sources
- ZWQ S200 Fire Rat — current Monkee Mods listing and specifications
- ZWQ S200S Viper — current Monkee Mods listing and specifications
- ZWQ S200 — current Monkee Mods parts category
Frequently Asked Questions
Are Fire Rat and Viper magazines interchangeable?
No. The ZWQ S200S Viper Magazine is explicitly not compatible with Fire Rat magazines, so identify your trim before ordering a spare.
How much faster is the Viper than the Fire Rat out of the box?
The Fire Rat is listed around 110 FPS with its stock spring fitted. The Viper is listed around 90-95 FPS on its stock spring and around 170+ FPS once its included 1.6 spring is installed.
Is there one holster that fits both trims?
Yes. The ZWQ S200/S FireRat/Viper Holster is the one holster confirmed to fit both the Fire Rat and the Viper.
Do I need to buy an upgrade spring separately?
No. Both the Fire Rat and the Viper already ship with a 1.6 upgrade spring in the box.
Other platform mod guides
ZWQ S400, ZWQ S100, Zius BK2S, Worker Harrier, Monkee Mods Firefly, Worker Seagull, Hare Diana, AIT Lightning, Zius BK1S, XYL KM9 Unicorn, Worker Kunlun, Worker Nightingale and QWK Challenger MK3 & Edge.