Well I liked my kids so much that I did another similar to hers, but didn’t go as extreme. I used a milspec buffer tube, modified MFT stock and my normal hiperfire 24c trigger. It comes in at 4lbs 7ozs.
all the skeletonized stuff looks cool, but there’s no real weight savings as the metal is thicker and heavier to compensate for all the cuts.
you can’t really go lighter on the bolt/buffer unless you plan on bunny fart only loads, otherwise it’ll beat up parts, your shoulder, and the dot will bounce like mad. In fact, my super light build bounces a bit much using 128pf loads and I’m thinking about putting the bolt weight back in to see if that will slow it down enough to reduce some bounce. Otherwise, I think I’ve found the limit (my limit) of lightweight vs double tap accuracy. My 5lb 8oz Gun will put shots about 1.5-2” apart at 8 yards. This super light puts them about 4” or more apart. This means I have to slow down my second shot on anything with distance, otherwise it’s C/D zone City...no bueno.
As for barrels, I think the only way anyone is going to get much lighter is to create a shrouded barrel system with a shorter steel barrel and titanium shroud (i’d be afraid how much that would cost).