The spars and gun barrels on the Rigby armed merchantman are made from grass stems.
The recoil tube on the PTA Priest howitzer is also made from a grass stem.
The correct shape for the machine gun barrel on the Priest was made by slipping a small grass stem inside a larger grass stem.
The grass stems must be painted to get the correct color and they can be made stronger with superglue.
Now is the time to go out in the fields and collect some grass stems before they are covered by snow.
The grass stems with the grass seeds at the tip are about three feet long.
I store my grass stems in the cardboard tube from a roll of paper towels.
My grass stems are less than one mm at the tip of the stem to about three mm at the base.
Chemically, grass stems are similar to paper so they work well with paper models and they are free.