In 1957, the Swiss finally adopted a self-loading infantry rifle after more than ten years of development and experimentation. The SIG Stgw57 was an improvement of the roller-delayed system designed by the Germans during WWII, and it was a very finely manufactured rifle (we would expect no less from Switzerland).
The Swiss also went headfirst for the “most clumsy looking rifle” prize – although I hear differing opinions on how comfortable or awkward it really is in use. Most of the ones available in the US are the semi-auto AMT model, which have become very expensive. Note the distinctive beer keg charging handle – a feature common to pretty much every Swiss rifle from the 1890s to the 1980s.
We now have a page in the Vault on the Stgw57, which includes a gallery of photos (high-res available for download as well) and a half dozen manuals in French, German, and English.