BRI, could you close up on those useless parts? i think the cylinder is the part of the barrel in the muzzle brake (the big thing at the end of the barrel), but the other parts? i need a better view. they probably go inside the model, so you wont need it. Check the 3d View without open faces (other configurations) and see inside and out. Also, find where it goes on the sheet and check cooresponding faces.
EDIT: ok, i found what they are. the one on the far left is the barrel piece in the muzzle brake, the far right goes on the sight, its a *chuckle* eyepiece (to go and block out the sun) its missing in your picture of the scope, so....BINGO! check the model, i missed it, but its unnessary to have. So is the other one.
havent quite figured out what the middle one is though....