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

You could put a tiny drop of super glue on the hole to seal it.

Are you using these in a reenactment setting?  I came up with the similar idea of using racquetballs about a month back and given the relatively small distances our battle demos occur in, etc., I found that they worked just fine straight out of the can.  I play racquetball with a bunch of friends from school (we're addicts), and I've gotten hit in the face with a racquetball a lot harder than you can sling one.  There was no damage as the racquetball collapsed into itself upon impact.  There wasn't any major kind of pain either, just stopped me in my tracks and think to myself "what the hell?"  I'm going to have to try the injected water idea now, but I still feel better about using regular racquetballs for demos as I know they aren't going to hurt or kill anyone.

Cheers,
Adam C.
The Greek Warriors & Legio XI

Cool, I bet one could pump a tennis ball with water putty to give it some weight w/out the chance of it leaking.