Rock River Varmint a4 info

My dad bought one for christmas, its one that he put together using a standard rock river lower with a skeleton stock and a varmint upper. The rifle seems to be a pretty good shooter, I shot it the other day at the range and seemed to shoot consistently sub 1/2 moa at 100 3 shot group with old surplus ammo in less than ideal shooting conditions ( about 20 degrees outside and wet. The rifle appears to be alot better than the colt H bar pre ban and the pre ban colt carbine my dad has. The components are tighter fitted. Just wanted to share the news