So it came out too small? Mind telling us (or even better showing us with pictures or a video) what effect that has? Mistakes can be just as informative as success. I imagine it probably doesn't slide in the barrel right, wiggling around way too much, but my mental model could always use more data.
Guessing the MX mount came out right, as you're experienced with those. But, again, 3D printing shrinkage isn't something I have a handle on, so who knows.