In the quest for soft ammo I started using water filled tennis balls but the fuzz is an aerodynamic drag and size is a bit large.
Racquetballs are nice and smooth and come in a 12 pack at $1.00 each.
The tangential introduction of a 22 g needle gives a (mostly) self sealing path to minimize leakage. I usually introduce the needle right in the first letter of the brand name on the ball to check for subtle leaks easily.
Leave the needle in the ball for the entire filling process. A 20 ml syringe is used to instill 52ml of water. (Don’t overfill or they do leak.) Alternately inject several ml water then pull back plunger to remove air. After the first 20 ml water is injected, pull out the plunger and fill the barrel of the syringe and repeat the process. Test for complete filling by absence of sloshing when shaking the ball and no more bubbles upon pulling back syringe plunger. Allow pressure to neutralize withg the plunger removed. Excess water trickles out the needle.
While these usually leak little, I don’t keep them near moisture sensitive equipment. I store them in a bucket. If they get squashed in the trunk under a bucket of rocks they leak plenty but then who wouldn’t?
Final results:
55mm ball weighing 100 gm that doesn’t hurt too bad if you know it’s coming.
Great for Slinger’s Catch and other games.
AjlouniBoy