SENTRY STALKING
If a target is attacked completely suprised (failed Spot Hidden + successful Sneak or Hide) at point-blank range, and that attack impales, the target can be instantly killed. Only one such attack can be made in a round. This allows characters to take out sentries with all manner of knives, silenced weapons, or their bare hands at close-range.

CALLED SHOT
Requires Precision Aim (see Call of Cthulhu, 5.5 ed, p.56; can use more than rifles) and requires rolling equal to or less than one-fifth of the applicable skill.

MOVING WHILE FIRING
A character can move their full 8 MOVE while firing a weapon, but this is unaimed fire. According to the rules for unaimed fire, the chance to hit is reduced to one-fifth of the normal percentage. If for some reason, the character is already using a form of unaimed fire (ie. firing two weapons), the chance to hit is reduced to one-tenth of the normal percentage. As always, the chance to hit cannot be reduced to less than 01%.