This was asked a while back,     So I thought I'd offer to show how I occasionally make them. I'm going to omit dimension's as lots of ppl have different type's of E-11 but there's often a ruler in the pic which may help out?   Either way I suggest you make a paper/plastic sheet template based on your own gun, before cutting anything expensive, aslo depending on the thickness of the leather that can tend to throw any global "fixed" template measurments out.   F