The rule system known as Square Bashing covers battles (not skirmishes) from 1900 right up until the Chaco War.
The rulesbook and army book are now available in PDF form. The rulebook is £9.00 GBP, and the army book £8.00 GBP. They can be ordered through the PP website. Square Bashing rules started in 1997, and the rules have a long and fine pedigree of usage. No hyperbole here, just the good experiences had by gamers. With PP rules, any size or maker of figures can be used with ease.
The name Square Bashing is based upon a combination of ideas. Square Bashing is the British army name for parade drill. In addition, it encapsulates the idea of a game using a square grid in which the squares effectively "bash" each other.