Rock River, for the money. I don't claim to be a great shot. I suspect the 'flier' in each of these groups is the first shot and caused by FRP from the suppressor (Silencerco Omega).
18" .223 Wylde ATH Upper 5 shot 100 yd group, Hornady Varmint Express 55gr, bags front/rear:
16" 6.8 SPC Coyote Upper, 5 shot 100 yd group, Fed Fusion 115gr, bag front/rear: