Why don't you have any confidence in a string loop? I have been using one for about ten years now and never has it failed nor have I ever thought it would fail. Once it is tied in it's not going anywhere.

I tried the ultra nock a number of years ago and did not care for it at all. The string loop is far superior to the metal loops out on the market.

I would rather shoot off the string with a double jaw release than use a metal loop.