Close Action is a set of free wargames rules for squad level WW2 actions.
Focused Firepower is a set of free wargames rules for playing WWII skirmish games. The authors write:
Focused Firepower is a scenario-driven 1:1 wargame designed for use with 1/72 scale miniatures. We have endeavoured to offer an in-depth game system with the focus on realism, but the system we have developed is easy to learn and games flow well.
As a 1:1 system the models you have on the tabletop represent the exact troops and vehicles. The majority of other game systems use a more abstract method where one unit actually represents several, or where entire units are modelled on a single base and dealt with as a whole. We found that our method provides a more accurate and realistic impression of real warfare.
By focusing our game on realism we have found that real-world tactics work just as well on the tabletop and we highly recommend reading the fantastic range of WWII tactics books published by Osprey.