The GBB
To switch from refrigerant to electric operation, it is necessary to replace the entire lower receiver assembly, pull out the outer tube assembly, and replace the chrysanthemum

If you plan to use the GBB mode, the receiver cannot be printed upright, it can only be printed lying down. Otherwise, the strength will not be enough. It is recommended to use PLA or PLA-CF for printing. Under the use of PLA-CF material, the GBB mode can undergo a 20-minute air pump pressure test and not be damaged.