The British designed Scout Experimental 5 (SE5) was one of the first successful air-superiority fighters:

Glenn Curtiss Museum-7530 by vcheng552000, on Flickr

Glenn Curtiss Museum-3892 by vcheng552000, on Flickr

Glenn Curtiss Museum-7525 by vcheng552000, on Flickr

Glenn Curtiss Museum-7527 by vcheng552000, on Flickr
In addition to the forward firing Vickers gun on the fuselage, the top wing mounted Lewis .303 machine gun had a special Foster mounting for changing ammunition drums in flight and for increasing the range of motion:

Glenn Curtiss Museum-7529 by vcheng552000, on Flickr
More here: Royal Aircraft Factory S.E.5 - Wikipedia, the free encyclopedia