After seeing the excellent Florida Bowling Ball Mortar built by Bill Tyrrell and displayed on this forum I decided I had to make one. After meeting with Bill and examining his mortar closely I decided to make mine very similar to his.
Not all the dimensions in building this mortar are critical. However the 29 1/8th inch circumference for the gas cylinder has to be that or a grunt more to accept a standard bowling ball.
I obtained an old welding gas cylinder with a bit smaller circumference than Bills but I decided to go ahead and practice with it. I cut the nose off leaving a flat spot to weld on a powder chamber. I then cut off the cylinder at 18 total length. The darn bowling ball would not go inside the cylinder. I guess I knew that would happen. This practice is documented on this forum under Practice For Bowling Ball Mortar Job.
Next I attacked a 29 1/8 circumference cylinder that I had. I did the same. Cut off the nose And then cut off the cylinder at 18 inches overall. The bowling balls fit nicely now and have A bit of windage (clearance) like there should be.


More description and photos to follow as this project moves along.