SILENCER MODELS - how to install them: see docs\2_HOW_TO_INSTALL.md, "Part 4".
UNZIP this folder first. In OpenIV import  ov_attach.otd  first, then the 5 .odr files. Then add the lines of default_ide_lines.txt to default.ide.
Models: "Silencers Pack 1" by Pedro Silva, CC-BY 4.0 (see CREDITS_SILENCER_MODELS.txt).
