What is "esser-barrat"

The Esser-Barrat rifle was an experimental slide-action firearm in the United Kingdom at the start of the 20th Century. It was essentially a development on the Austrian Steyr-Mannlicher M1895 straight-pull bolt-action rifle, but with the bolt connected to a pump on the for-end of the stock.

The firearm was tested in Bisley Ranges, Bisley, Surrey in 1906, but never adopted for military use.