Who knew? Is it your experience?

[Yogi]

I had some cooper coated .22 pellets that had corroded.  Tin is not waterproof!  They were extremely accurate in my Diana 340 N-tec.
I assume that the corrosion grabbed the lands and grooves very well.

https://noricaairguns.com/en/noricas-copper-coated-pellets/#:~:text=The%20copper%20coating%20reduces%20the,down%20power%20at%20any%20distance.

-Y

[Airnut]

The byproduct of copper corrosion is copper oxide. Copper oxide is used as a anti friction and anti wear additive in some lubricants. As to grabbing the rifling better the opposite may be true.
It would be interesting to test both corroded  and uncorroded pellets to see if their are any measurable differences.
I would quess there would be a slight velocity increase due to less engagment of the rifling with the corroded pellets.
This leads me to a question that I have been trying to figure out for some time now.
How much rifling engagment do you actually need for accuracy in a airgun?

[Back_Roads]

 I had a couple guns that would only shoot copper plated domed pellets very accurately, any other pellets basically shotguned in. They are very slippery so my assumption they slipped past bad riffling

[Airnut]

James
 Your post got me to thinking and thats usually a bad thing!
I have a problem child that will not group with any pellet but have never tried the copper clad pellets. The crown and rifling are good as per a bore camera. Pellets will be here today so we will see.