Take a full length of No. 4 tubing, out a branch about 3 inches long at a point about 2 inches from one end; leave the end of the branch closed (Fig. 78). Now load the branch with shot or coarse dry sand, and your repeating air gun is ready for use.
Tilt the branch slightly above the horizontal and blow intermittently. Does your gun reload after each blow, until the ammunition is used up?