Problem with comp tip masthead and halyard

Here is a picture of the halyard.
http://imgur.com/qNW66NG
The copper "slug" was pretty rough with nicks and lumps, and looked a little fatter than the rope section, so I carefully used a dremel with a sanding roller to smooth it and slightly reduce the diameter. But then I think I melted whatever bonds it into the rope, and the slug actually moved out of the rope by about 1-2mm. Going from bad to worse!

Anyway, when I tried it in the masthead this morning it rubbed, but it was no longer totally jamming as it was before. Having decided I've probably ruined it anyway and will need to by another, I went the whole hog and cut a ring about 3mm long off the end. Now it goes through even easier, but still with some rubbing.

I guess if it fails I just have my main fall down and I have to sail back on the jib. Should I use it or just buy a new one?

By the way, I don't think the masthead is sloping back, I think the photo was mis-leading because the mast was slightly rolled to one side, so the perspective was off...