Brass oarslocks are supposed to be able to be bent to match your oars. DONT get them too snug. They are designed to be able to flex enough that with a sharp, hard pull you can pop the oar up and through the thing. Its for safety. If you hang up the oars on a rock or root wod and you are in serious trouble, being able to pop the oar might be your savior ( trust me, if you're ever in this situation, you'll have enough adreneline to do this IF they weren't too tight to begin with.) If you ever have to do this, a padded vise is nice to tweak them back that little bit you bent them popping the oar out. A length of pipe to gently bend them out a little works well. BTW, a spare oarlock at $20 is a good insurance policy too, just like a spare oar.