Super Mutt gun.
Spear Upper, Virtus 6.75 guts, Legacy handguard.
Eta: Looking for a Legacy upper to help even things out.
Eta:2
Well to no ones surprise, you get tighter fitment using a Legacy Upper with Legacy handguard.
Imo, the VC XTN works better with aluminum handguards. The carbon hg needs the longer rail groove on the legacy upper to be secure.
Since I had everything stripped down, here are some weight comparisons incase anyone nerds out like me.
Stripped Upper receiver weights (no BCG or CH. Includes FA weight or FA delete respectively)
Legacy: 1lb 1.9oz
Virtus: 1lb 3oz
Spear LT: 1lb 0.8oz
Rattler: 1lb 1.1oz
Polymer Forward Assist: 1.4oz
Legacy Aluminum Forward Assist: 2.2oz
FA Delete: .5oz
Virtuous Concepts MCX XTN: 0.5oz
Rattler 556 Handguard: 6.1oz
Lancer Carbon Fiber 10in: 5.9oz