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View larger RetroArms NGRS SiCr progressive spring M150 is a shortened upgrade spring designed exclusively for Tokyo Marui Next Generation Recoil Shock (NGRS). It is made from silicon-chromium (SiCr) alloy valve spring wire, has an outer diameter of 13.75 mm and features progressive winding for easier initial compression.

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7215
RetroArms CNC TM NGRS M4 Gearbox – 8 mm is a precision-machined upgrade for Tokyo Marui Next Generation Recoil Shock M4 and HK416 platforms. The redesigned construction offers reinforced critical areas, improved cable routing and optimized cylinder support. A spring guide is also included for proper compatibility.
7229
RetroArms CNC Piston with Steel Rack – 14.5 Teeth is a new-generation piston designed exclusively for Tokyo Marui Next Generation Recoil Shock (NGRS). Its CNC-milled POM-C body is paired with a rack made from 1.7102 spring steel hardened to 52–54 HRC. The design is engineered for high mechanical loads and long service life.
7223
RetroArms CNC TM NGRS POM tappet plate is designed for Tokyo Marui Next-Gen EBB gearboxes (SRE / SOPMOD) used in airsoft replicas such as AR15, M4, 416, MK18. It is made by CNC milling from Ertacetal-C (POM), which combines durability and flexibility. The precisely machined front section helps ensure correct nozzle guidance and makes nozzle adjustment...
7680
RetroArms CNC cylinder head for Tokyo Marui NGRS is designed for Tokyo Marui electric airsoft guns with the Next Generation Recoil System (Next-Gen / SRE / EBB). The cylinder head features impact damping and a long nozzle for proper operation in an NGRS gearbox. It is manufactured using precise CNC milling and, when correctly installed by an experienced...
RetroArms NGRS spring is specially designed for Tokyo Marui Next Generation Recoil Shock (NGRS / SRE) gearboxes and, compared with springs for standard AEGs, features a corresponding shortened design and an outer diameter of 13.75 mm. It is made from silicon-chromium (SiCr) alloy valve spring wire, which, according to the manufacturer, retains its stiffness and shape even after several thousand shots. Progressive or variable winding makes compression easier during the initial stage of piston movement. During installation, the tightly wound section of the spring should face the spring guide. The manufacturer guarantees compatibility only with TM NGRS gearboxes. Dimensionally, the spring also corresponds to springs used in the VFC Umarex MP7 AEG and LCT QM Series, but RetroArms does not guarantee its compatibility with these systems. The spring is not designed for conventional AEG gearboxes. The resulting performance of the build cannot be determined solely by the spring rating, as it is also affected by the air seal, barrel and other components of the specific gun.
RetroArms springs are colour-coded for easy identification of individual ratings. The M designation indicates the approximate velocity the spring may achieve with a 0.20 g BB in a conventional, properly sealed build. Actual performance is also affected by air seal, cylinder volume, barrel length and diameter, hop-up bucking, weight of moving components and the overall tuning of the gun. The performance and range values in the table are therefore approximate and not guaranteed.
| Spring rating | Colour coding | Estimated velocity with 0.20 g BB | Estimated energy | Theoretical range | Ideal BB weight |
|---|---|---|---|---|---|
| M100 | Yellow | approx. 100 m/s | approx. 1.00 J | approx. 45 m | 0.20–0.23 g |
| M110 | Orange | approx. 110 m/s | approx. 1.21 J | approx. 50 m | 0.23–0.25 g |
| M120 | Red | approx. 120 m/s | approx. 1.44 J | approx. 54 m | 0.25–0.28 g |
| M130 | Purple | approx. 130 m/s | approx. 1.69 J | approx. 59 m | 0.28–0.32 g |
| M140 | Blue | approx. 140 m/s | approx. 1.96 J | approx. 63 m | 0.30–0.36 g |
| M150 | Green | approx. 150 m/s | approx. 2.25 J | approx. 68 m | 0.32–0.40 g |
*Note on range: The stated theoretical maximum range does not represent the distance at which the gun will accurately and consistently hit a target. In practice, usable range is significantly affected by the quality and adjustment of the hop-up system, suitable BB weight, performance consistency, barrel and weather conditions. Higher power therefore does not automatically result in a proportionally longer or more accurate range.
When installing a progressive spring, the tightly wound section (where the coils are positioned closer together) should face the spring guide. RetroArms marks this section with a colour for easy identification of the spring rating.
No. This version is specifically shortened for Tokyo Marui NGRS gearboxes and is not intended as a replacement for a standard AEG spring. RetroArms offers a separate range of springs for conventional AEG gearboxes.
The tightly wound section with the coils positioned closer together should face the spring guide.
According to the manufacturer, the spring dimensions also correspond to springs used in the VFC Umarex MP7 AEG and LCT QM. However, RetroArms guarantees compatibility only with Tokyo Marui NGRS, so use in other systems is not covered by a compatibility guarantee.
| Variants | M150 |
| Color | Green |
| Muzzle velocity (m/s) | 150 (m/s) |
| Body/receiver material | Metal |