The RIS Version in the GHK M4 Gas Blowback Rifle Series gets a quick review from Bunny Workshop which have this in stock right now... "The GHK M4A1 RIS Gas Blowback has a wew HOP-UP system, with version 6.0 hammer, and stable bolt lock. It has steel made bolt carrier and CNC fishbone rail with the inner barrel being a precision one at 6.03mm. The bolt is adopted by impact-resistant material with a German made connect spring. It is flexible, not easy to break, but easy removal and maintenance; which is also save gas for high airtight characteristic.

The barrel has very detail heat pattern, which is OEM by Montblanc. Steel thin-walled, light weight, and hollow center, the whole process of producing barrel is almost the same level as real gun.

Diluted phosphoric acid manganese is used as surface treatment, which has double the cost compared to manganese. This makes the product rustproof and scratch-proof.

The gas consumption of M4 magazine is larger than G5′s mag. M4 magazine can shooting 1 and 1/2 mag a time in auto mode; 2 to 3 mags in semi mode.

Sling mount can be installed with any single, 2- or 3- point tactical sling."