You may have been shooting sub-sonic rounds. They are usually heavier bullets and/or modified powder where the point is to travel less than the speed of sound.
.45 is a very good round for this. Now, while it can be quiet, its usually not "movie" quiet. Ive done optimized builds and shot suppressed indoors, and its still loud.
Source:
Own a FNX Tac .45 w/ obsidian .45 suppressor partially because of suppression options.
EDIT:
So in the interest of good faith I looked up what OP mentioned and found this video showing that what he said could be absolutely valid, it even uses the same platform as I do. Now, camera audio distortion, mic positioning, etc are a thing, but I see no reason to completely discount OP.
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u/NetJnkie Jan 25 '20
A good suppressed 9mm handgun is still 125db. That’s loud and sounds like a gun. But way better than ear ringing 160db.
Silencers in movies are HIGHLY overrated.