Build & buy · Silverback Airsoft
Build your SRS
The Silverback SRS A2/M2 is the most upgraded bolt-action platform we sell. Pick a base rifle, then build it with the Stalker parts we develop and test ourselves.
01Start here
Pick your SRS
Three official lengths. Everything below fits all of them unless the part says otherwise.
02Where accuracy starts
The hop-up chamber: pick your system first
The chamber is the single part that changes an SRS the most, and the choice drags everything else with it: the chamber decides which buckings and which inner barrels you can run. This is not a matter of taste, it is two different systems.
We recommend the Kraken, and not because it carries our name. The stock unit is honest about taking generic AEG rubbers; the Kraken was designed against the two historical weak points of the SRS: air seal and alignment. It is modular and self-aligning, so the bucking and nub sit straight without shimming tricks, it fits in about two minutes, and it ships with the patented twin-lip Kraken bucking. The result Silverback quotes is around +20 FPS on the same spring, purely from not leaking air.
Kraken: Standard or Ultimate V2
The Ultimate V2 is the revision that came after 22+ five-star reviews on the V1: a smaller front head to cut bolt friction, and a stainless steel body that holds high hop pressure without flexing. It also fits the Silverback HTI. The Standard uses the same modular system and the same bucking; if you are not going to run heavy hop, it is plenty.
The stock FAST unit and the standard unit
These stay in plain sight rather than buried: they are official Silverback parts and for a lot of people they are enough. The FAST unit is CNC 6061 aluminium and its whole point is that it adjusts in the field with no tools, in seconds — there is a left-handed version too. The standard unit is the plain factory chamber. Both take AEG buckings and AEG barrels, not VSR ones.
03The rubber that touches the BB
Buckings
The bucking is the only part of the rifle that actually touches the BB, and it has to match the chamber you picked above.
The Kraken buckings are the VSR-type side: the Gen 2 concave is the current one, the Gen 1 is still stocked for builds already set up around it, and the SR hop bucking covers SRS and TAC-41. Concave means the contact patch wraps the BB instead of pressing on a single line, which is what keeps a heavy BB stable at range.
Silverback flat hop, by hardness
These are the AEG-side rubbers for the FAST and the stock chamber, sold by durometer: 50, 60, 70 and 80. Lower number = softer = more grip and more hop for the same adjustment, but it deforms sooner under a heavy spring. Higher number = harder = holds up to hot setups and heavy BBs, but needs more pressure to bite. On a 2.8 J rifle with 0.40 g, the 60–70 range is the usual starting point.
04Bore and length
Inner barrels
Two Morpheus lines, and they are not interchangeable, because they answer to the two chambers above.
Why SUS304 and not the SUS303 nearly everyone else uses: 303 machines faster because its composition is tuned for exactly that, and it pays for it in corrosion resistance. 304 is more expensive to cut and lasts longer in a barrel that lives in damp woodland.
And why a dual bore: the rear section is tighter to control the BB right after the hop, then the bore opens up so air pressure is not still fighting the BB on the way out. A single tight bore gives you consistency and drag; a single wide bore gives you speed and wander.
Which length for your SRS
Other Dual Bore Hybrid lengths (18)
The 6.03 AEG line
Only if you are keeping the stock chamber or the FAST.
Morpheus AEG barrels (9)
Inner barrels from other brands (82)
05Air system
Pistons
The piston is half of the noise your opponent hears. It is not only about how much energy it moves, it is about how it stops at the end of the stroke.
The Stalker Scorpion lets you tune piston mass, cup and airbrake, which is the way to soften the mechanical slam without giving up energy — an airbrake traps a cushion of air ahead of the piston so it decelerates instead of hammering the cylinder head. The Silverback Variable Mass is the factory part and plays the same mass-tuning game. Both are shown here, side by side, so you can compare them properly.
06Air system
Cylinders
The SRS runs on a fixed working volume. The cylinder does not change that volume — it changes weight, friction and noise.
Stalker takes three angles: the Teflon Silenced goes after noise, the Lightweight after mass and cycling speed, and the Fluted Gold is the fluted version. The Silverback stainless steel is the factory part and the toughest of the four — also shown here, not hidden away.
07Energy
Springs, joules and the legal limit
Every spring in this section is 13 mm outer diameter, the SRS / TAC-41 / SSG / VSR size. Rapax are hand-made in Europe and their pitch is not only power but running quieter, which matters on a rifle built around being silent.
To play in Spain: 2.8 J
This is the one most people buy. It ships with a spacer, because no two builds are sealed identically — the spacer is how you dial in just under the limit instead of going over it.
The Rapax scale, by power
We quote the colour grades rather than exact joule figures on purpose: the real energy depends on your cylinder, your air seal, your barrel and your BB weight. Two rifles on the same spring do not chrono the same.
Silverback, rated in newtons
Silverback labels by spring force in newtons instead of joules: 90 N, 100 N, 120 N, 150 N, plus the M130 and M150. More newtons means more compression force and more energy, but also a harder bolt pull, more piston slam and more mechanical noise. There is a point where a stronger spring costs you more in stealth than it gains you in range.
08External
Outer barrel and carbon extension
Outer barrel and carbon extension are in one section because they are fitted together: the extension threads straight onto the 24 mm outer barrels — the G-Spec ones (A1 and A2) and the 16" and 20" Sport barrels.
That is the trick behind the integrated-suppressor look. Instead of hanging a can off the muzzle, the carbon extension sleeves over the barrel and continues the line of the rifle. Two sizes: 165 mm and the XL at 465 mm, both 30 mm in diameter. Straight from the manufacturer’s own documentation: Silverback CBX user manual (PDF).
Outer barrels
Fluted in 16", 18" and 22", plus the G-Spec. Outer barrel length does not improve accuracy on its own — the inner barrel and the hop do that. What the outer barrel decides is the silhouette, the weight out front, and which extension you can thread on.
Or a conventional suppressor
If you would rather screw a can on than sleeve the barrel: 24 mm CW thread, the same interface as the barrels above.
09Mounting
Top rails
Three of these are A2/M2 top rails and one is not. Read your receiver before you order — Silverback is explicit that the A2/M2 rails fit the M2 variant only, and are not compatible with the SRS A1 or the plain SRS A2.
Flat A2/M2 rails: short or long
The difference is how much they cover. The short one spans the receiver plus the short handguards (HDG-06 aluminium or HDG-07 polymer) and ships with 7 screws and 2 M-LOK nuts; the long one covers the receiver plus the long HDG-05 handguard, 8 screws and 3 nuts, so the optic and anything mounted up front share one continuous rail with no step between them. 6000-series anodised aluminium, licensed Desert Tech.
The canted rail, and when you actually need one
There is a canted option: the long A2/M2 rail also comes in a 30 MOA canted version, sloped down at the front towards the barrel. What that buys you is usable elevation adjustment. A scope has a finite amount of internal travel, and the further out you zero, the more of it you burn just holding the crosshair up. Tilting the whole rail down at the muzzle gives the scope back that travel, so you are not sitting at the end of the turret at distance.
The trade-off: on a flat rail your mechanical zero sits in the middle of the range, which is where you want it for close and mid work. At the 2.8 J the law allows in Spain you will not run out of elevation, so for most players here the flat rail is the right answer and the canted one is for export builds and open-limit fields.
For the A1
One rail here is not an A2/M2 part at all: the SRS Long Handguard Rail (SRS105) is nylon-reinforced fibre and fits the SRS-A1. Note it does not fit the Covert handguard (SBA-HDG-02).
10Feeding
Magazines
The SRS uses its own magazine. Three materials: aluminium 30 BB, steel 30 BB and lightweight ABS 25 BB. Steel survives being dropped on rock; ABS is the one to carry when you have four on your belt and every gram counts; aluminium sits in between.
11Bolt handle
Bolt knobs
The bolt knob is pure ergonomics, and on a bolt-action that is not a small thing: it is the part you work between every single shot, usually with a glove on, usually without taking your eye off the scope.
By weight, since that is the real difference: the Light knob is the minimum at 20 g, the Vauban is 21 g in fibreglass-reinforced nylon with a steel nut, the Bakelite is 23 g and the original SRS shape, and the Carbon and Grip knobs are the heavy end at 38 g. The Grip one is the interesting one: it carries NBR80 O-rings for grip and is threaded on both sides, so you can extend or shorten the bolt handle to suit your reach.
The Match, Tactical, Operator and Twisted knobs are the CNC 6061-T6 shapes for the SRS bolt head, all generations — despite what some of the product URLs suggest, these are knobs, not trigger units.
12Optics
Scopes and mounts
Optic and mount are one decision. Get the mount wrong and a good scope will not hold zero, whatever you paid for it.
The two numbers that have to agree are tube diameter (25.4 mm / 1 inch, 30 mm, or 34 mm) and height — enough clearance for the objective bell to sit above the rail without touching it. The adjustable and split-ring mounts below cover the common combinations; the Silverback DTSM handles 34, 30 and 25 mm.
Scopes
13Ergonomics
Stock
The A2 nylon stock, as a spare or a replacement.
14Trigger group
Trigger units
Last on the page on purpose. A trigger upgrade is the finishing touch: it will not add a metre of range, but it is what stops you pulling the shot off target at the moment of release.
Silverback’s range runs from the Sport unit through the Dual Stage Classic up to the Match and Speed versions. Dual stage means there is a defined take-up before the wall, so you can hold at the break point and squeeze through it deliberately instead of yanking a single-stage trigger. Match is tuned for the lightest, most predictable break; Speed is tuned for the shortest reset.
There is also the A2 trigger unit, the direct factory replacement.