I note that Longarm uses an EOTech, although it looks like the one that takes the "AA" batteries. I like the 551 myself, although there are now (surprise!) newer models. And he should put it on an AR carbine and put an ACOG over the 20" barrel. JMNSHO!
Dunno what his BUIS is; there are so many to choose from. I use the ARMS #40L myself.
I think Oleg Volk just slapped any handy sight on Longarm’s A2.
I agree, that rifle needs optics with some magnification to get the most out of it.