I have found it to stretch, but not more than anything else I've tried. When I was first starting out, I went to buy a B-50 string for a 55lb osage bow I had made. The guy at the shop said it was a recurve string, but when I got home it was for a compound. The knock loup was obviously for a bolt and not for a knock. I modified it to make it fit, and when I put it on the bow, it stretched it right out and the bow straightened up completely. I twisted the string and it stopped stretching and worked. If you do the same with art. sinew and just put a few twists in it like you would any other material, it will hold pretty well and stop stretching. I've got artificial on all my bows and some are 65lbs, no problem.