The discussion of the new PA prism sight mentioned KillFlashes to mitigate the emitter being visible from the front. I don't have one of the prisms, but have seen the phenomenon from other red dots. I've had good luck 3D printing killflash type thingys. The price is certainly attractive if you have access to a 3D printer. I attached an image of the rendering, and below the scad file. OpenSCAD is a free CAD program - it inputs the file below (and you change the dimensions (in mm) to whatever your sight needs, and OpenSCAD produces a .stl file that you can print (after slicing it with the slicer of your choice).
It's a good excuse to get your kids a 3D printer for Christmas :-)
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Code:
$fs=.1; $fa=.1;
hex_dia=5; //this is the 'diameter' of the hexagons, i.e. the dia of
//the circle that would just contain the hexagon
hex_wall_thickness=0.6; //the wall thickness between adjacent hexagons
hex_height=5; // height of the hex mesh
OD=30.1; //overall outside diameter
ID=28.1; //inside diameter (to fit over optic)
overall_height=9; //overall height of mesh+part over optic
// make the rim above the hex mesh, to fit over optic
linear_extrude(height=overall_height) translate([OD/2,OD/2,0]) difference()
{
circle(d=OD);
circle(d=ID);
}
//build the exterior tube plus hex mesh insert
linear_extrude(height=hex_height)
// we build a circle and then subtract the grid of hex holes
difference()
{
translate([OD/2,OD/2,0]) circle(d=OD);
{
// build hexagonal mesh (we build a rectangular 'beehive' grid
// of hexagons, larger than the circle OD. Each hexagon is the
// size of one of the hex holes).
for (j=[0:((OD/hex_dia)/2)+1])
{
for (i=[0:(OD/hex_dia)+1])
{
translate([j*hex_dia*1.5+(hex_dia/2),i*hex_dia*cos(30),0])
circle(d=hex_dia-(hex_wall_thickness/2),$fn=6);
translate([(j*hex_dia*1.5)+hex_dia*0.75+(hex_dia/2),
(i*hex_dia*cos(30))+(hex_dia/2*cos(30)),0])
circle(d=hex_dia-(hex_wall_thickness/2),$fn=6);
}
}
} //end hexagonal mesh
}