SRS GUIDE - Silverback SRS A2/M2
The complete guide to your Silverback SRS A2/M2: every component explained, the best STALKER and Rapax upgrades, and the science behind each one. You can buy upgrades progressively or in complete kits — and if you prefer, we install the upgrades for you.
Table of Contents
- Hop-Up Chamber
- Hop-Up Buckings
- Nubs
- Piston, Ideal Weight & Shortstroke
- Airbrake
- Cylinder
- Joule Creep
- Springs, Power Rings & Power Tuning
- Outer Barrel
- Suppressors & Silencers
- Triggers
- Body & Accessories
- Magazines
- Maintenance
- Hop-Up Adjustment
- Upgrade Path
- Complete STALKER Kits
- SRS Replicas
Why the Silverback SRS?
The Silverback SRS is an airsoft replica licensed by Desert Tech, based on the bullpup SRS-A1/A2 design. It is considered one of the best sniper platforms available:
- Bullpup — Long barrels in an ultra-compact package (from 56cm / 22")
- High air volume (~41cc) — Ideal for heavy BBs and joule creep
- Tool-less disassembly — Spring change in seconds
- Full modularity — Barrels, stocks, handguards are all interchangeable
- CNC aluminium — Machined receiver with Desert Tech license
1. Hop-Up Chamber
The hop-up chamber is the most critical component of any sniper. It controls how backspin is applied to the BB, directly affecting range, accuracy and consistency.
Our recommendation: the Kraken Ultimate Edition V2. It includes everything you need — CNC chamber, S3 arm, concave bucking and Prowler nub — for a complete hop-up upgrade in a single package.
The Kraken SRS features TDC (Top Down Center) adjustment with centred pressure, interchangeable S2/S3 arms, and full compatibility with concave buckings, SR-Hop and Prowler/Tigra nubs. It is the market reference for the SRS.
If you already have a Kraken chamber or need to replace a specific part, we also sell individual pieces:
▶ Individual Kraken parts
▶ Stock Silverback chamber
2. Hop-Up Buckings
The hop-up bucking touches the BB directly. A good bucking makes the difference between 10cm and 30cm groupings at 60 metres. There are two types of STALKER bucking for the Kraken chamber, each with its own philosophy:
Kraken Concave Buckings — Maximum seal and precision
The Kraken concave buckings wrap around the BB with their concave profile, creating a larger contact surface and more uniform backspin. But what makes them special is the seal engineering: they are manufactured to exact dimensions to fit perfectly between the nozzle, the Kraken chamber and the Morpheus inner barrel. There are no gaps or air leaks — every STALKER component is designed to fit together, and that perfection is what makes the difference in shot-to-shot consistency.
Best option: buy the 3-hardness set to test which works best with your setup:
- 50° (Pink) — Softest. Warm climates, 0.40-0.46g BBs
- 60° (Purple) — Most versatile. Recommended for most setups
- 70° (Orange) — High power (3.0J+) with 0.45-0.50g BBs
▶ Individual concave buckings
SR-Hop Buckings — R-Hop without the hassle
The SR-Hop buckings emulate the R-Hop concept (extended contact patch along the barrel window) but in a drop-in format: no cutting or gluing patches required. They apply less hop than the concave buckings by design, but in return they are more progressive and adjustable — ideal if you want finer backspin control or use very heavy BBs where excess hop is counterproductive.
Just like the concave buckings, the SR-Hop are manufactured to the exact dimensions of the Morpheus inner barrel, ensuring a perfect fit with no gaps. Kraken chamber + SR-Hop/concave bucking + Morpheus barrel = a system designed as one unit.
▶ SR-Hop buckings
▶ Stock Silverback Flat Hop buckings
Summary: Kraken concave = maximum hop and perfect seal, the default choice. SR-Hop = less hop, more adjustable, ideal for long-range setups with heavy BBs. Both share the exact dimensions of the Kraken chamber and Morpheus barrel.
3. Nubs
The nub presses the bucking against the BB. A good nub applies uniform, centred pressure, eliminating side curves. The Prowler + Tigra set is the best investment: try both and keep whichever groups best.
- Prowler: Concave design, uniform pressure. The most versatile
- Tigra: Concentrated contact, ideal for SR-Hop/R-Hop with heavy BBs
- Low Profile Prowler (LPP): Low-profile version for limited space
▶ Individual and rubber nubs
4. Piston, Ideal Weight & Shortstroke
The piston is the heart of the SRS. It compresses air and pushes it through the hop-up chamber. The Scorpion SRS Ultimate Edition includes the piston, spring guide, modular weights and airbrake — everything you need to transform your SRS:
- Integrated airbrake — Stops the piston at the end of its travel, reducing noise
- Modular weights — Steel and aluminium to fine-tune performance
- Interchangeable heads — Extreme Stealth or High Joule
- Scorpion spring guide — Smooth and consistent travel
▶ Other Scorpion versions
Ideal Weight: 82 Grams
82 grams is the perfect weight for the SRS piston, the result of years of testing. At 82g you get:
- FPS consistency — Uniform air delivery shot after shot
- Maximum joule creep — Optimal air volume with heavy BBs
- Smooth cycle — No bounce against the cylinder head
- Silence — The airbrake works optimally at this weight
Combine the Scorpion piston with steel weights (head + body). Weigh on a precision scale and adjust to 82g.
Shortstroke — Scorpion Exclusive
The Scorpion is the ONLY piston on the market that allows shortstroke configuration with modular weights. It has 5 weight positions (4 steel + 1 aluminium). By installing 4 weights instead of 5, you reduce the piston travel and available air volume.
What is it for?
- Lower joules without changing the spring — Less air = less power. Ideal for fields with strict limits
- Reduce noise — Less air volume = softer piston impact
- Adjustable — Add or remove weights as needed. The volume is fully tuneable
- Power cap — Limit maximum energy so you never exceed field limits
No other piston on the market offers this functionality. It is an exclusive advantage of the Scorpion's modular design.
▶ Individual weights and components
▶ Stock Silverback pistons
5. Airbrake — Fine Tuning
The airbrake controls how the piston stops. Its adjustable disc regulates how much air is delivered before braking:
- Disc retracted — High power (2.5J+): maximum air delivery
- Disc extended — Low power (<2J): prevents piston bounce
Rule of thumb: If you hear a double “clack” when firing, the piston is bouncing. Extend the airbrake disc further. Bounce destroys consistency and damages components.
| Power | Setting | Reason |
|---|---|---|
| 3.0J+ | Nearly retracted | Maximum air delivery |
| 2.0-2.5J | Medium | Power/control balance |
| 1.0-2.0J | Extended | Prevent bounce, maximum silence |
| <1.0J | Fully extended | Priority: prevent bounce |
6. Cylinder
The cylinder determines air volume and cycle smoothness. Our recommendation: the Teflon Fluted Silent Cylinder — teflon coating + interior fluting = minimum friction and maximum silence.
Combined with the Scorpion Piston + Airbrake, it makes the SRS nearly inaudible at game distance.
▶ Other cylinders
7. Joule Creep
Joule Creep occurs in replicas with high cylinder volume like the SRS (~41cc). With heavier BBs, kinetic energy increases even though velocity drops — the BB stays longer in the barrel, receiving more push.
| BB | FPS | Joules | Joule Creep |
|---|---|---|---|
| 0.20g | ~450 | ~1.88J | Baseline |
| 0.28g | ~395 | ~2.03J | +8% |
| 0.36g | ~360 | ~2.16J | +15% |
| 0.40g | ~345 | ~2.21J | +18% |
| 0.46g | ~320 | ~2.19J | +16% |
How to take advantage of it:
- Heavy BBs (0.40-0.46g) — More real joules, better stability, greater range
- 82g piston — Gradual push that maximises heavy BB acceleration
- Long barrels — More travel = more acceleration time
Important: Always verify with a chronograph and your game BBs. Joule Creep can cause you to exceed the limit without knowing it.
8. Springs, Power Rings & Power Tuning
The spring determines power output. The SRS uses 13mm APS2 springs. Changing the spring takes literally seconds thanks to the bullpup design — open the stock, remove the spring, insert the new one and close.
Silverback Springs (Stock)
| Spring | Power | Use | Price |
|---|---|---|---|
| APS 60N | ~0.8-1.0J | CQB | 12.25€ |
| M90 | ~1.0-1.3J | CQB+ | 12.25€ |
| APS 100N | ~1.3-1.5J | Light outdoor | 15.15€ |
| APS 120N | ~1.5-1.8J | Outdoor | 15.15€ |
| M130 | ~1.7-2.0J | Sniper | 12.05€ |
| M140 | ~1.9-2.2J | Sniper | 11.90€ |
| APS 150N | ~2.0-2.5J | Open field | 15.15€ |
| M160 | ~2.5-3.0J | High power | 11.95€ |
| M170 | ~3.0-3.5J | Maximum power | 11.90€ |
Rapax Springs — RMS vs APS2
Rapax springs come in two formats:
- APS2 — Standard format, longer. Compatible with all SRS pull-bolt models
- RMS (Rapax Match System) — Shorter, designed for greater adjustability. Includes ABS spacers as standard for fine FPS tuning. More compatible with power rings due to shorter length
If you want maximum fine-tuning capability, choose the RMS format. If you just need a spring at a fixed power level, the standard APS2 works perfectly.
| Rapax | Power | Type | Price |
|---|---|---|---|
| APS2 1J | ~1.0J | APS2 | 19.95€ |
| APS2 2+ | ~2.0J | APS2 | 19.95€ |
| RMS 2+ | ~2.0J | RMS | 19.95€ |
| 2.8J | ~2.8J | APS2 | 17.95€ |
| APS2 3+ | ~3.0J | APS2 | 19.95€ |
| RMS 3+ | ~3.0J | RMS | 19.95€ |
| RMS 4+ | ~4.0J | RMS | 19.95€ |
| APS2 4+ | ~4.0J | APS2 | 19.95€ |
For 2.8 joules, our recommendation: Rapax 2.8J spring + 420mm inner barrel. This is the sweet spot for this power level.
FPS Adjuster Rings (Power Rings)
The steel FPS adjuster rings from Rapax let you tune power without changing or cutting the spring. They install on the spring guide as preload washers, increasing spring compression and raising FPS in a controlled manner.
Combined with RMS springs (which are shorter and leave more space), you can fit more rings for a wider adjustment range.
Spring Cutting — Manual Adjustment
If you need a fine adjustment that you cannot achieve with rings or washers, you can cut coils from the spring:
- Cut 1-2 coils at a time maximum with a Dremel or pliers
- Each coil reduces ~20 FPS on M130, ~30 FPS on M190 (approximate, not linear)
- Chrono test after EVERY cut
- It is irreversible — if you cut too many, you will need a new spring
Always start with power rings. Only cut the spring as a last resort.
▶ Spring guides and washers
9. Outer Barrel
The outer barrel determines overall length and which inner barrel you can use. From G-Spec (309mm) to 26" (680mm):
| Barrel | Inner | Thread | Price |
|---|---|---|---|
| G-Spec | ~309mm | 24mm CW | 42.35€ |
| 16" Fluted | 420mm | 14mm CCW | 84.65€ |
| 18" Tapered | 470mm | 14mm CCW | 69.95€ |
| 18" Fluted | 470mm | 14mm CCW | 96.75€ |
| 22" Fluted | 590mm | - | 108.85€ |
| 25" Twisted | 650mm | - | 149.95€ |
| 26" Fluted | 680mm | 14mm CCW | 130.95€ |
▶ Barrels and accessories
10. Suppressors & Silencers
Suppressors are among the most useful accessories for the SRS. While in airsoft they don't “silence” like real firearms, they serve very practical purposes:
- Noise reduction — Internal foam baffles absorb the “pop” of air exiting the barrel when firing
- Inner barrel stabilisation — The suppressor wraps around the barrel tip, reducing vibrations and improving accuracy
- Concealment of upgrade barrels — If you install an inner barrel longer than the stock outer, the suppressor covers it aesthetically
- Tactical aesthetics — Complete the sniper look of the SRS
DTSS Silencers — With acoustic foam
The DTSS (Desert Tech Sound Suppressor) are Silverback's functional silencers. Made from CNC 6061 aluminium, black anodised, with a unique serial number. They include acoustic foam baffles that absorb the sound of the shot. Available in .30 and .338 calibre (cosmetic diameter difference).
Also available in QD (Quick Detach) version with the SRS's native 24mm CW thread — they mount and dismount in seconds:
You can use the DTSS to extend your inner barrel using the barrel spacer:
Carbon Suppressors (Mock/Dummy)
Carbon suppressors are cosmetic — they don't contain foam, but they stabilise the barrel and cover extensions. Carbon fibre body with CNC aluminium end caps. Ultra-lightweight. Available in sizes S, M, L, XL, XXL with 24mm CW (SRS native) or 14mm CCW thread:
▶ All carbon suppressor sizes
Thread Compatibility
The SRS uses 24mm CW thread natively. Silencers and muzzle brakes with 14mm CCW thread (standard airsoft) can be used with our adapter:
DTSS-compatible muzzle brakes accept DTSS silencers directly:
▶ DTSS-compatible muzzle brakes
11. Triggers
The trigger doesn't affect ballistic performance, but it does affect the shooting experience. The Match is the choice of most snipers: dual stage with exceptional tactile feedback that lets you feel exactly when it will fire.
- Match (Dual Stage) — The best option. Adjustable preload
- Classic (Dual Stage) — Dual stage with defined travel
- Speed (Dual Stage) — Fast reset for consecutive shots
- Sport — Basic, functional, affordable
▶ Other triggers
12. Body & Accessories
▶ Bolt Knobs
▶ Stocks
▶ Handguards
▶ Rails
▶ Other accessories
13. Magazines
The SRS uses proprietary magazines. Available in aluminium, steel and lightweight ABS:
▶ Metal magazines (30 BB)
▶ Lightweight ABS magazines (25 BB)
▶ Magazine accessories
14. SRS Maintenance
The SRS is extremely easy to maintain thanks to its bullpup design and tool-less disassembly.
Spring Change
Changing the spring takes literally seconds: open the stock, remove the spring guide and spring, insert the new one and close. No tools needed. In a conventional sniper (VSR, etc.) this requires receiver disassembly — with the SRS you can do it in the field between games.
Cylinder and Piston Lubrication
Use WD-40 PTFE DRY (dry teflon spray) on the internal cylinder walls and the piston's O-ring:
- Disassemble the piston and cylinder
- Apply the PTFE DRY spray on the cylinder walls and O-ring
- Wait ~3 hours for it to dry completely
- Reassemble
Dry PTFE creates a teflon layer that reduces friction without attracting dirt — unlike conventional grease or oil that accumulate dust and debris.
- Don't over-lubricate — a thin coat is enough
- Don't do it every game — every 3-4 months or ~2000-3000 shots is sufficient
- Never use silicone oil inside the cylinder — it can deteriorate hop-up buckings if it migrates through the barrel
Inner Barrel Cleaning
Run a cleaning rod with a microfibre patch through the inner barrel. A tiny drop of silicone spray on the patch, 2-3 passes, then a dry patch. Do this every 5-10 game days or when you notice accuracy loss.
15. Hop-Up Adjustment
Correct hop-up adjustment is the difference between erratic shots and consistent hits at 60+ metres. The SRS features the FAST system that allows field adjustment without tools.
The Correct Technique
- Start with hop-up fully deactivated (the BB drops quickly)
- Adjust gradually upwards — each click adds pressure on the bucking
- Fire 3-5 BBs per adjustment to verify consistency
- Continue increasing until the BB starts to rise slightly
- Back off just a little — the BB should fly flat or with the slightest rise
This is the sweet spot: maximum range with a stable trajectory. Too much hop = the BB rises uncontrollably. Too little hop = it drops early.
Important Tips
- Always test with the BB weight you will use in game — hop-up behaves differently with 0.20g vs 0.43g
- In cold weather, the bucking hardens — you may need more hop-up pressure
- After every bucking or nub change, re-adjust from zero
- With the Kraken SRS, TDC adjustment is more precise and centred than the stock hop-up
16. Upgrade Path — Progressive Buying
You don't need to buy everything at once. The SRS can be improved gradually. Here's the recommended order, from highest to lowest impact:
- Hop-up (Kraken + bucking + nub) — The biggest accuracy leap. You go from 30cm to 10cm groupings at 60 metres
- Piston (Scorpion) — Noise reduction, FPS consistency, joule creep utilisation
- Cylinder — Complements the piston. Additional noise and friction reduction
- Spring — Adjust power to your field's rules
- Outer barrel — Length, aesthetics and capacity for longer inner barrels
- Trigger — Ergonomics and shooting feel
- Suppressor — Additional silence and stabilisation
We install upgrades for you — if you buy the parts at Skirmshop, we can install them in your SRS. Contact us for more information.
STALKER kits (Starter and Ultimate) include the most important parts at a reduced price compared to buying them individually.
17. Complete STALKER Kits
If you want the complete upgrade without complications:
Ultimate Kit — From 352.95€ (Recommended)
The complete transformation: Kraken hop-up, Scorpion piston, cylinder, bucking, nub, inner barrel. Range, accuracy, silence and consistency at their best.
Choose the length based on your outer barrel: 420mm for 16", 510mm for 18-20", 570mm for 22-26".
▶ All Ultimate kits
Starter Kit — 163.95€
Scorpion Piston + cylinder + calibrated spring. Ideal if you already have a hop-up or want to improve only power and silence.
18. SRS Replicas
SRS A2/M2 16" Sport — From 453.75€
Entry to the SRS platform. Compact, lightweight.
SRS A2/M2 16" Covert — From 568.65€
Tactical version with long handguard. Perfect for stealth.
SRS A2/M2 22" — From 598.95€
Maximum range with long barrel. For distance snipers.
SRS Full Upgraded by Skirmshop — 2.8J
Replicas fully assembled and tested by our workshop with all STALKER upgrades installed. Ready to play.