i bought a new complete upper. but the forward assist will not engage the bcg. just slips right by it when you pull the bcg out while holding the FA inwards. i replaced it with my other bcg and it engages like it is suppose to. this video is another issue im having when shooting .223 55g. but when i shoot 5.56 nato i have no issues.. changed buffer spring no fix. this video is not mine but have the same problems..