First, could it be you don’t have the correct Phantom flash suppresser?
My Colt 14.5 inch M4 barrel with Phantom measures 16.250 inches.
It has an 1/8 inch or less of the original peel washer.
It is common practice to use either a Phantom or Vortex to bring a 14.5 inch
barrel out to the legal 16 inch limit. The flash suppressor must be permanently
attached to qualify.
Barrel length is measured from the bolt face, (bolt being closed) to the end of the
barrel. This length includes any permanently attached extensions, muzzle breaks
or flash suppressors. The best way to measure this, insert a cleaning rod into the
barrel with the bolt closed, place a piece of tape on the rod at the end of the barrel,
remove rod and measure. If the muzzle device is removable, it must be removed
to determine the correct length.
Possession of a short barreled upper receiver and complete lower could be
construed as intent or conspiracy to manufacture an illegal short barrel rifle.
Your best bet would be to keep them as far apart as possible, maybe leave the
lower at an acquaintance's house until you’re up to par.
If you have anymore questions or problems, ask away.
[b]R[/b]ighteous [b]K[/b]ill