Odd shape when printing

Hi, very new to 3D printing but think I am getting there. I was printing a replacement bracket for my Mendel but the bolt holes keep appearing as oval and not round. I have tried a couple of other prints and the same thing happens to them. I have re-calibrated my axis but the problem is still there.

I'm using a Bowden extruder, 0.4 hotend and the Z axis are 5mm threaded rods.

Thanks in advance for any advice.

Is the height of the part ok?
If not it would indicate that your z-axis needs the steps calibrated.
Have you tried to print the part rotated so the holes are printed vertically?

Thanks for the advice. I think the parts are coming up short. I'll double check the z axis and adjust if necessary then reprint the part.

I say Z axis calibration as well.
Use this very nice calculator here: RepRap Calculator - Prusa Printers
Scroll down to Steps per millimeter - leadscrew driven systems, Then input everything you know. For me, this gave me a value of 4000 steps per millimeter.

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Master Tinkerer

A calculator is a good start but in most cases it won't come close to the realty.
As said, assuming is one thing, confirming by measuring is making sure.
If you want to aim in on an error or problem you can not assume, you have to confirm all is they way you expect it to be
According to the calculator I need 1660 steps for my z-axis, but to be on the true and correct side I need to use 1680 as otherwise the Z-axis start to run out after a few cm of printing.

Turned out it was the Z axis. One of the nuts on the threaded rods were popping out of the X axis motor mount bracket.

Thank you all for the help and advice.

Good you got it sorted!