Hmmm... I smell an Instructables...
Airsoft FN-SCAR metal frame - ~$200USD with Amazon Prime
2.4 GHz yagi antenna - ~$15USD with Amazon Prime
Holographic picatinny rail sight - ~$30USD with Amazon Prime
Assorted electronics - $???USD
Weekend of father/son kit-bashing and tinkering - Priceless
Icon, 'cause building a RotM drone death-ray is thirsty work --->