Accuracy fixed.

[brian y]

I have gotten uppers that had been ceracoated and the internals were not masked before applyign the coating. The result was that the inside diamater was reduced to almost "too small" with excess material. If yours is ceracoated, the tool may not be the problem.

These are hard coat anodized but you can see from the pics the tool goes in when inserted from the other end and sticks when inserted in the proper end;
I do not know if you can tell from the second photo but it seems there is too much material and it is butting up to it and stopping the tool from going in, and before anyone asks this is not how I was planning on using the tool, I just put it in the vise this way to take the pics lol.