Picatinny rail attachment for a World War 2 British Sten Gun MkII, MkIII and MkV. Five slotted rail, hinged so it can be placed behind the magazine well. Use any 1/8in dowel or large cotter pin for the hinge or print the 'StenRail - Hinge Pin'. The width of the bottom is 3/4in and fits right in between the ejection port and charging handle slot. Use a #5 nut in the bottom. I don't think heat from the gun will be a problem given where its suppose to be placed but use ample infill anyway after all its going to be holding a sight/scope.
StenRail - Top.stl
This top is the tallest and most bulky but also very sturdy.
StenRail - Slim Top.stl
As you can see its shorter than the previous verions but still very strong with proper infill.
This version is .2in wider and will has a larger ID so the sight/scope and bi-pod are perfectly vertical. This top will only work with the corresponding bottom (Bottom_w-Rail.stl). As pictured the bottom also has rail, this can be used for grips or bi-pods.
I designed the 'iron' sights as well with a slot for a sling, these are available for sale at GunBroker.com
If you have any fitment problems please leave a comment!