Most popular handgun: Beretta 92F/FS or 1911. Both are very popular in movies, but I suppose Beretta takes top spot because of its notorious reliability and blank convertability to armorers.
Most popular shotgun: Either Remington 870 or Mossberg 500.
Most popular rifle: Hell if I know.
If you really want to know based on IMFDb statistics, go to special pages and see which images link to the most pages.
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