lego semi auto rifle (brickshooter)

hi here is my new gun its a semi auto brickshooter, i havent made my mp5 yet but it will come up maybe in next weak. there is not much to say about it. oh there is one thing, it is a very simpel mech so for them who are new with this kind of stuff is this a good starter mech. i will may or not make instruction for it.