What is shown is a standard garden hose cover for the male end of a hose.

The thru-hole is made with a #18 Drill bit, [from the inside of cap against a block of wood], which locare over a #11 ML nipple.

You can add a small o=ring if you want to.

Dis-mount the barrel from stock and place on the nipple and turn the hose on slowly, [you will get a bit wet] and the loaded charge will pop the bucket below the muzzle.

You will recover the bullet and fertilize the grass after wards as the powder charge is wet.

Hose adapter ML 13 Dec 2022.jpg