3d Printable Rifle buffer. This is for traditional semi auto function only. It will cause issues with full auto and forced reset triggers (bolt bounce), but should work with binary.
Best paired with an adjustable gas block to retune the rifle for the reduction in total reciprocating mass, but will still work with a standard gas block.
Best printed out of hard TPU or my favorite, PCTPE.
Its nice for a light weight build option, competition, or simply democratizing manufacturing.