I wanted to test the theory of barrel scratches, I took 3 barrels, brass, aluminium and stainless steel. Did a borescope video before on all 3, then used a nylon cleaner brush 15 passes on each one, then cleaned with tissue and isopropanol, then another borescope video. I was expecting perhaps some scratch on the brass but nothing on any of them. Just be 2 cents worth.
@Yashy Have a watch on YT at how to remove and clean an inner barrel, it will also explain to you about how to clean and remove the hop chamber and hop rubber. If you plan on playing quite a lot this information will really help you get the most out of your AEG.