The secret-sauce is I had Louis at Acculite cherrypick me three matched barrels, a Midwest STAP-SF rail-mount folding buffer-tube adapter for AR stocks and lots of discontinued Leapers 3-slot QD optic risers as QD adapters. (STAP and pistol slingmount each screwed onto one, optic mounted atop another.) Folding grip is the same FAB Defense one used on USAF GAU-5 ASDW's. The thumbrest and angled foregrip are also FAB Defense, I've found that when positioned together as pictured the two pieces give a VERY solid lockup with the support hand--a neighbor thinks my braced Mk 18 pistol thus configured gives every bit as much control without a stock as his Mk 18 SBR with one.
If I were doing this again, I'd dump that SOPMOD for an M4 wafflestock--it's just too big and bulky even though the rear-end weight helps with balance.
That blue tape? I'm trying to find a crapped-out, defect or otherwise scrap Midwest 10/22 handguard that I can have somebody cut back to about there for the 6" barrel. The bare barrel fits but IMO looks kinda Bubba, out of step trying to go for a slick high-tech "Bond Movie Gun" feel.