I like doing things the hard way. So when I forgot I had my 5.56 cap on my Verse 36 I found out the hard way that 9mm will indeed force itself through a 22 caliber hole. It had to shed its jacket into the suppressor but it went through. The original cap was only slightly deformed and required some high heat to remove it after 2 rounds of 9mm but the new cap I have will definatly never meet that fate and they are a quality build.