I read your last info on a metal suppressor being quieter when wrapped with cloth. I have a .25 caliber air rifle for which the last few inches of the barrel is a suppressor plus I added a suppressor, aluminum, without baffles. It makes a little more noise than my suppressed rifle for .22 shorts. However, I wrapped it with a towel and it was noticeably quieter. If I tap the barrel or suppressor with a fingernail it rings like a bell so your suggestion makes a lot of sense.