NO offense meant, but IF your intending on shooting a rifle in NRA sanctioned Highpower events, you've some more reading in store for ya.
The have rules and regs on rifle configurations, which, from your post above, would prevent the use of this rifle in sanctioned competetion, (not sure if this is your purpose).
Competetion rifles have a free-float "tube" underneath the actual rifle length handguards. As stated above removal of the float-tube under the handguards is specific to DCM/CMP rifles and the fact that like you, some folks jump too far to fast and fail to do the proper research.
Improper installtion of this barrel your referring to would result in lousy groups, something no competetor wants (a rifle that don't shoot straight).
My advice for you is slow down, more reading, less posting. Things will be clearer to ya then,
Mike
added: BTW, Welcome aboard
, your in the right place to to learn about firearms and AR15s in particular,