The villain is always foreign; if devious, Oriental; if ruthlesslt efficient, German (or these days, Eastern European); sadistic baddies are often Russian/East European; For any of these (and all other major villains) a British (preferably English) actor can be substituted.
A weapon capable of putting a bullet 15 inches into seasoned oak at point blank will be succesfully stopped by cheap furniture.
In a western, the hero can pick off a target at a range several times greater than the effective range of the weapon he is using.
The hero often has "duplex" ammunition, capable of taking out two or more persuing "baddie" extras with one shot. In most screen gunfights (all periods), nobody ever gets hit by "stray" bullets (unless it's to get the hero involved/more committed).
Any dying comment made by a character is relevent to the plot.

Regards

Walrus