SA M4 B04

The Specna Arms brand SA-B04 carbine replica made predominantly of an homogenous alloy of zinc and aluminum with the use of steel elements in the most neuralgic points of the replica ( the screws, the pins and the tactical sling attachment points are made of steel ). The SF type stock which holds the battery and the pistol grip were made of polymer plastic. 

The replica uses a quick main spring exchange system, the so-called Enter & Convert™. This allows for a quick and fluent adaptation of the replica’s power to the conditions of the battlefield without the need of having access to a workshop or a number of specialist tools – when you take the gearbox out the replica’s body, the process of exchanging the main spring takes literally seconds.

The replica was fully adapted to cooperate with LiPo and LiFe type batteries.

The gearbox which is reinforced on the height of the cylinder’s head hides a steel main spring guide which is the element of the Enter & Convert™ system and also 8mm ball bearings and steel thread-wheels which are placed on spacers. The system is secured with the use of four anti-reversals. There is a type 2 cylinder and the steel breaker. Replica is factory-fitted with and accurate, rotary type polymer Hop-Up unit that allows very precise and stable regulation of BB overclocking.

The Upgraded Version is equipped with some new, improved internal parts:

- set of reinforced steel gears
- steel spring guide
- lightweight, polymer piston
- aluminum, sealed piston head
- metal cylinder head
- air seal metal nozzle