the two v3 and v4 with the LDT HK416 are wonderful, having said that The only shot in HK416 v4 will be more stable due to the mosfet mounted. the two versions provided by AKgelblaster will come with metal gears.
NOTE: https://haseebzwan129718.ka-blogs.com/81479043/hk416-gel-blaster-manual-options