Scotpirate, We use hot soapy water, dry and hose down with WD-40 after firing like thousands of other folks who maintain their cannons in a rust-free condition. What lots of competition shooters will not tell you is that there is a secret cleaning process they use after each shot DURING THE CONTEST. This technique uses basic chemistry to reduce one important variable. This technique affects consistency of shot to shot velocity. Velocity is very important in obtaining accuracy and should be kept as consistent from shot to shot as possible. We have always weighed each powder charge on a scale before loading our aluminum foil cartridge to reduce the velocity variable.
So, even if you do not compete with your cannon, if you want the best possible groups, reduce the velocity variable by using an Alcohol sponge AFTER your regular DRY sponge After your regular WET sponge between shots. As most of you already know, DRY sponges don't stay DRY for very long!
WHY USE ALCOHOL?? Basic chemistry. Alcohol will dissolve water in any proportion and vice versa. Ethanol, (grain alcohol) works best. PGA (pure grain alcohol) is inexpensive and available at any liquor store. Yes they will combine in your alcohol sponge and all remaining water will be extracted from the bore. SO WHAT??? Why is this important? Water forces part of the powder's energy to be wasted as it is used to convert the liquid water into STEAM. SO WHAT? With a portion of it's energy used up, the energy available to push the cannon projectile down the tube is reduced which, in turn, reduces the projo's velocity causing it to hit the target lower expanding the group's size. That's why.
A very experienced BP artillery competitor friend told us this about 5 years ago and it is logical and makes sense to us. We Have not had the time to check it out with lots of experiments, but it's on the list of things to do. Retirement is less than 2 years away now!
Tracy and Mike
