I changed the standard buffer to a Spikes Tactical St-T2 buffer, which is heavier and uses powder rather than solid weights, so it eliminates the rattling sound that regular buffers can make in recoil.

Not much else to do with the internals. The BCG has chrome lined carrier and gas key and the gas key is properly staked. I suppose that you could swap the BCG for an M16 style BCG that has a little more weight, but a heavier buffer is cheaper and the gun has functioned perfectly with the factory BCG.

I added a Vortex Strikefire red dot sight.