Some people had the time to do independent tests.

Back in 2012 there were guys on Snipers Hide or Shooter's Forum that put Copper bullets in Copper fouling bore cleaner solutions, while weighing the bullets before and after.

Typically Bore tek lost no weight and the KG12 bullet lost 1.8 grains overnight.

If you want to relive 2012, there is a new scale I got for $18 that is very accurate and precise.
https://smile.amazon.com/gp/product/B0731F3F2N/

There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. -Ernest Hemingway
The man who makes no mistakes does not usually make anything.-- Edward John Phelps