The GAP 10 is a custom match grade system, better barrel, trigger, built on POF match billet upper and lower and so on. Usually .50 moa or better with the right ammo and shooter. Just better quality than the average AR-10.
1) Time spent on parts and fitting 2) Quality of materials 3) Parts are all custom fitted together ( not ) just parts produced then slapped together 4) Price and warranty
Actually AR-10 is an Armalite trade mark for their Semi-Auto 308....which parts are not compatible for LR308/SR-25 Semi-Auto 308's....most use the term generically referring to both... GAP 10 is a LR308 style rifle obviously.... I agree with the above posts.