The Gewehr 41 is a very interesting automatic rifle. it was designed in Germany, and used during World War Two. It was made by both Walther and Mauser(the variants can be seen above) What makes this firearm so unique is that it was made under the specification that it could not have any porting in the barrel. This presents a huge problem because most automatic rifles use a gas system that has a port in the top of the barrel, with either a piston or by direct impingement the bolt is pushed back to load the next round. As a way around this, the G41 instead uses something called the Bang system(named after Søren H. Bang) The way this system functions is by having a cone over the end of the barrel(which can be see in in the lower picture as #4) This cone creates a chamber that holds presure when the gun is fired, that pressure is used to push back a cylindrical piece of metal(part #6) which in turn pushes back a long piece of metal(not pictured) that moves over the barrel all the way back to the bolt and resets it. It’s an interesting system but it is prone to fouling and jamming up from being too dirty.