Well had a similar situation on a shield ... try wiggling the slide and frame to work it on or off.
you may not want to hear this but I had to get a rubber mallet and beat the slide forward. it came off
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Pistol caliber suppressors can be shot wet, but not rifle caliber suppressors. Also, there is such a thing as too much ablative material. Adding too much will build up excessive pressure inside the suppressor. In the best-case scenario, this can result in a messy firing...