GHK M4 Keymod MOD2 GBBR: specs, joules & FPS
Complete specs GHK GBB (gas blowback)
GHK M4 Keymod MOD2 GBBR: 1.56 J, 410 FPS, 2,960 g, 40 rounds. Full specs from the official source, with FPS for every BB weight.
Power
Above Italy's 1 J limit
Italian shops sell versions tuned below 1 J: ask the shop which version they ship.
Energy computed from the velocity with 0.20 g BBs, the standard weight manufacturers and shops use to measure FPS.
For information only, based on the source's data for this version. Not legal advice: always check current local law and the version the shop sells.
Technical specifications
| Brand | GHK |
|---|---|
| Model | M4 Keymod MOD2 GBBR |
| Category | Assault rifles & carbines |
| Power source | GBB (gas blowback) |
| Platform | AR/M4 SERIES |
| Weight | 2,960 g |
| Length | 778 mm |
| Magazine | 40 rounds |
| Hop-up | Adjustable |
Weighs 2,960 g: heavier than 60% of GBB replicas in the same category in the database (314 with weight).
Similar alternatives
Replicas of the same type and category that stay within the Italian 1 J limit.
| Replica | Energy | FPS | Weight |
|---|---|---|---|
| ARCHWICK Colt Canada L119A2 British Special Forces Rifle AWS GBB (Ultimate Edition) | 0.95 J | 320 | 2,810 g |
| EMG Noveske N4 M4 GBB (MWS System) by Double Eagle - DE (Gen2) | 0.95 J | 320 | 2,750 g |
| Tokyo Marui URGI MK16 MWS GBBR (11.5 inch SOPMOD Block 3) | 0.84 J | 300 | 2,710 g |
| Tokyo Marui M4 MWS (ZET System) GBBR M4 | 0.73 J | 280 | 2,960 g |
| Tokyo Marui M4 MWS Carbine (ZET System) GBBR M4 | 0.73 J | 280 | 2,960 g |
Velocity with different BB weights
At the same energy, heavier BBs leave the barrel slower. Expected velocity with the most common weights:
| BB weight | FPS | m/s |
|---|---|---|
| 0.20 g | 410 | 125 |
| 0.25 g | 367 | 112 |
| 0.28 g | 347 | 106 |
| 0.30 g | 335 | 102 |
| 0.32 g | 324 | 99 |
| 0.36 g | 306 | 93 |
| 0.40 g | 290 | 88 |
Theoretical calculation at constant energy (1.56 J). Real-world values can differ slightly with hop-up and replica.
Data source
The values on this page come from the product page of the shop redwolfairsoft.com, checked on 2026-11-07. The manufacturer does not publish full specs: values may refer to the version that shop sells.
Shop product page ↗ redwolfairsoft.com
Spotted a wrong or missing value? Let us know.