Round for 4 in. Mortar

[smokemjoe]

Friend has the steel for a 4 in. mortar, A 12 oz. coffee can will just fit, What else can be used to make a round. Thanks- Joe

[Cat Whisperer]

The tall 32oz or so juice cans.
Oil cans, now plastic though.

BUt you've got the addiction - everything that's round gets evaluated as A) a projectile or B) material for a mortar or cannon.

Pick something that is common.  Beer cans changed in 1974 to having the rim SMALLER rather than larger than the rest of the can.  RIGHT after I made a morter for them.  BUT Soup cans are still made that way.