Stalker Scorpion Piston for SRS & VKS – Modular Adjustable Weight Piston

Take full control of your bolt action sniper with the Stalker Scorpion Piston, a modular, weight-adjustable piston built specifically for the SRS and VKS platforms. Whether you want a plug-and-play upgrade or a fully tuned build, this piston lets you fine-tune weight, stroke and air brake settings to get a quieter shot, more consistent FPS/joules and a smoother bolt pull.

Why Choose the Stalker Scorpion SRS/VKS Piston?

• Adjustable piston weight – configure from approx. 62 g up to 145 g using interchangeable aluminium and stainless steel weights.
• Noticeably quieter rifle – adjustable air brakes soften the piston impact and reduce firing noise.
• Improved joule and FPS consistency – shot after shot, for tighter groupings at long range.
• Two adjustable air brakes included – short and long, to match your spring and power level.
• Short stroke option – add body weights to shorten the stroke for faster cycling and a shorter bolt pull.
• Open Piston Sear compatible.
• Best performance with the Stalker SRS/VKS Cylinder.

How the Modular Scorpion Design Works

Unlike a conventional one-piece piston, the Scorpion's body is formed by stacking six interchangeable weights. Mix aluminium and stainless steel sections to set the exact mass your build needs. Adding extra weights also shortens the stroke: this reduces cylinder volume and slightly lowers output, but makes every reload quicker. The lost power can easily be recovered with a stronger spring.

Body and head weights included:

• 5 × black anodised aluminium body weights – 3 g each
• 4 × polished stainless steel body weights – 11 g each
• 1 × black anodised aluminium head – 7 g
• 1 × polished stainless steel head – 17 g

Available Weight Configurations (6-piece setups)

*Requires a 5th stainless steel mid-section weight, sold separately.

Adjustable Air Brakes: Fine-Tune Silence and Power

The air brake controls the piston's speed at the very end of its travel. This shortens the time air takes to leave the cylinder and cushions the impact against the cylinder head, making your SRS or VKS much quieter. Once set, a locking nut under the cup holds the air brake firmly in position. A sorbo pad on the cylinder head can still be used alongside it.

• Short air brake (3.80 mm) – ideal for builds around 2 J–3 J and above.
• Long air brake (3.80 mm) – ideal for builds around 2 J and below.

The piston also comes with a high joule cup (polished finish) designed for higher output and an easier bolt pull.

Setup & Tuning Tips

1. Lubricate the cup edge with a drop of oil (motor oil, silicone oil or similar) for maximum efficiency.
2. For ~2.3 J builds, start with the short air brake fully unscrewed.
3. For 2.8 J+ builds, start with the short air brake fully screwed in.
4. Rule of thumb: more power = shorter air brake; less power = longer air brake.
5. Start low and unscrew the air brake gradually until the rifle becomes silent.
6. If you begin losing joules, you've gone slightly too far: screw it back in a little to regain power while keeping it quiet.
7. Always set your hop-up for your chosen BB weight so the rifle shoots straight.

Many factors affect how fast the piston accelerates: spring power, BB weight, bucking hardness, inner barrel length and piston weight. That's why adjustable air brakes make such a difference. Spring guide spacers are also a great addition for experimenting with spring tension and output.

Performance reference: in an SRS fitted with a Stalker SRS/VKS cylinder, a 420 mm inner barrel and a Rapax Lightpull Blue 2J+ spring, the Scorpion delivers approx. 2.2–2.3 J. With the stock cylinder, output will be lower. Results may vary depending on your setup.

What's in the Box

• 1 × Stalker Scorpion stainless steel spring guide (with engraved Stalker logo)
• 1 × Shock-absorbing rubber insert for the rear of the spring guide
• 1 × High joule piston cup (polished)
• 1 × Aluminium piston head
• 1 × Stainless steel piston head
• 5 × Aluminium body weights
• 4 × Stainless steel body weights
• 1 × Stainless steel sear end cap (15 g)
• 2 × Adjustable air brakes (long and short)
• 1 × Air brake locking nut
• 10 × O-rings to stop weights from loosening
• 2 × Spring guide O-rings for the SRS A2 butt plate
• Front and rear POM guide rings

The Ultimate SRS & VKS Piston Upgrade

If you're after a quieter, more consistent and fully customisable airsoft sniper piston, the Stalker Scorpion is one of the most versatile upgrades available for the SRS and VKS. Order yours today at Skirmshop and build your rifle exactly the way you want it.