Working in a pro shop I have seen the metal loops damage the string and some that also hit the buss cabals, Not all bows but, some. I started tieing loop back in 1993 on mine and have come up with diffrent thing to solved some of the prombles we had back then and it must be getting around because I see bows come in the store and at national shoot where people are do the same little thing as myself. A tied in string loop is the best way to go, I have only had one that broke in all the years I have used them and that one was my fault it was on a bowfishing rig and the string was worn out. Never have had one come untied.