Well getting off my ass and finishing my lightweight built. I'd say I am 80% done now, just missing a lightweight BCG, lightweight buffer, gas tube, gas block, and pinning the muzzle device. I'll gain .8 oz with the V7 gas block and maybe .1 oz with the tube but then plan to lose a bunch with a high end BCG.
The barrel and hand guard are not torqued down. I only put them on hand tight to check and make sure everything fits. So that's why there is an egregious hole between the upper and handguard.
For reference, an unloaded milspec M-4 weights 6.36 lbs.