M1918a2 Browning Automatic Rifle

My Real Steel BAR mags came today, going to take the top off them and put my M14 Midcaps inside them! They're the Belgian 1s, not as expensive as the US 1s

Here is the rear iron sight I have been working on, the casting was made out of bronze courtesy of Warren, the rest is 2mm thick aluminium bent into angle trims, then cut down.

Fathoming how to affix the bar through the middle of the holes, a) so that it lines up and b) is stiff enough to stay in either up or down position when I am running!