Don't believe anything you read on the internet

It is common sense that an individual rounded dice with drilled pips will have bias. However, it is folly to believe that a randomized rounding process will with regularity import the same bias.
I would highly recommend gathering data yourself, over the course of 1000 rolls of a box of chessex dice, so you can see if your dice are actually seriously unfair or if you are a victim of confirmation bias.
That being said, most 'precision' dice are square cornered/edged or larger than 'normal' dice, so beware if you try to acquire sets of >20 that you will need for
40k games. Also, square cornered dice are actually far more easy to manipulate when rolling, such that I don't actually trust people who use their 'lucky square dice' to make single dice rolls: this is the reason that casinos require dice to bounce a long distance and/or off a wall to make it a valid throw.
If you still want to get some precision dice,
this thread recommends www.godbama.com and www.koplowgames.com .