for the smaller parts like the casing deflector, and the layoff barrel tip, and the bayonet lug, you can use small holes drilled into them and apply aluminum rivet pins
into holes in the tube. then with e6000 again to complete the bond.
before you primer those areas, you can add some model putty to create a stronger bond, over the glue, to add some thickness at the base of the join.
then after primer and paint, a nice dull mattte coat of plastic paint in clear helps to give everything a layer of plastic
over all these fragile parts, and you can pretty much trust it from there...