The standard #3 barrel link has a great fit between the lug opening, with true square corner edges. It has enough clearance to freely move and keep the barrel nice and straight with no excess wiggle room. I put it on a new 1965 H&R military A1 barrel that came with a rejected 1966 colt slide that Springfield armory used that year to build the Camp Perry 1911A1s for their pistol matches. I installed it to test on a 1948 colt government model 45 auto. The slide has a flush even finish with the rear frame. Best by far I have used.