Hi,
I have had the 'honor' of making a couple thousand of these forts
Here is the process:
Most hobby as well as arts and crafts stores sell the balsa wood doll-rods that are 2-3 feet long. Buy a couple of these rods that are about 1/2" x 1/2" square.
Cut these square rods into appx. 1 inch long pieces using a fine toothed saw or an exacto knife.
Next step is to take your exacto knife and share off two corners of the 1" long square block at 45 degree angles - so you are left with one side of your square block being an inch long and the other side looking like the three sides of half a hexagon.
Next step is to take your exacto knife and carve out the gun slite on the 45 degree angled side of the block. In about the middle of the block, just niche out a small indentation with you knife along all the 'walls' of the 45 degree angled sides of the block.
Next, shave the top (roof) of the block with an exacto-knife so that the roof slopes down slightly on the sides of the block that you gun slit is on.
Finally, buy a spool of wire at a hardware store that is about the same diameter of a 1/300th miniature tank barrel. Cut them into 1/4" long pieces and stick them into the gun slits (by either jamming them into the balsa, or dipping them into a bit of glue before jamming them into the balsa) to be your bunker's main gun.
Once you spray paint your bunker the color of your miniatures it looks pretty good.
hmmm - after reading this - I can see how this may not be easy to follow - so let me know if you have any follow-up questions. The "Spring 1944" picture on the "Game Design" page of website ( - of the website - not the forum) has a decent picture of a fortification in France made this way.