There are no competition pellets (outside of the 10-meter Olympic range). It's a matter of finding different brands, different weights, different speeds, different batches, and doing a lot of testing and taking a lot of notes.
When you find a pellet that your barrel likes, try matching the velocity to that pellet, and if it really works well, write down the brand, write down the batch number, and buy as many pellets as you can from that brand and batch. There are no perfect pellets.
If you're looking for more precision, you'll need to wash them, lubricate them, sort them by weight, check for concentricity, and use a magic wand to make all the work you've done pay off. It's about scraping a little bit from all sides, perfecting your shooting technique, being consistent and repetitive.