Submit you ammunition requests to the NRA via a grant request. Place orders with the CMP (and wait in line). You can always try the "spot market" stores such as Sportsman Guide, Ammoman, etc . The NRA is very supportive of the BSA, 4H, and YMCA shooting programs as are the ammunition manufacturers. The main issue is submitting your request using the required documents & providing all information necessary. There are many groups doing this every year. I don't know of a better way to obtain 22LR for youth shooting sports.
"Protect Your 2nd Amendment rights - Join the NRA" - Hunting Bear