I've gone retro, but am only half way there......

[USMC88-93]

So I found some new old stock A1 barrels a long time ago. Then found couple of upper receivers (do not know if they Are M16A1 uppers or Sp1 uppers) both are small front pin. Then I found someone that had some unused A1 straight delta rings, weld spring and clip. Now all I need to do is properly mount and torque the barrels to the uppers and install a gas tube and flash hider on both.

And it appears impossible to keep dog hair and dust out of close up pictures taken on the floor.