No idea what your experience level is with the AR, but I can assure that if you attempt to use a hacked up lower like that it would allow foreign matter to get into places it shouldn't.
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if you need a lower that grabs attention and is 'skeletonized' and isnt opened up to the dirt, sand, etc then maybe 'the jack' from sharps brothers would satisfy those criteria for you.
lighter?... maybe not.