Get it started manually so that it's in the notch of the new line above the bracket. From there simply the clip it with a small ball-peen hammer gently but steadily and it will slowly work its way in until it's nice and tight. It's better to be slightly tight then way too loose. And yes, not all the hard line connectors are machined exactly the same as they are made. I've experienced an entire set of new stainless steel lines which I had to do the procedure above. Just make sure you hit the clip and not the hard line.
Al
P.S. Really a hammer works here.
