Bracket is made of 1/8" thick plastic card (same thickness as the magnets)
I mark off a square a little larger then the magnet for the base and a rectangle for the stand that the HKM will be glued too.
Drill a hole in the base, the same size as the magnets
Cut out the pieces
Glue the stand to the base with plastic glue, so they are perpendicular
glue the HKM's to the assembled bracket
drill a hole in your tank where ever you want to put them, put a magnet in the tank and in the bottom of the bracket with super glue.
For the twin link Plasma gun I used Plasma guns that came with the space wolves sprues. I cut off the grips, drilled small holes to match the mount, then put a small piece of plastic card between the two to make them match up.