I am about 99.9% positive that they are the aluminum beer bottles that Bud/Bud Light come in. I am half way done making a WBS, just gotta cut the neck down to fit upside down inside of the base, then pop rivet the sucker together. Measuring for the inside part is gonna require some exact measurements, so that the shoulder of the neck part fits just right inside of the base, and the end of the neck just hits the bottom of the base (does all that make sense?). If/when I ever get it done I will let you know...