Bob, given the recent Olympic events, your activity sounds like a lot of fun for the boys (BB Guns and skis). You probably had everything covered, but for others reading this, please be aware of the BSA policy about this kind of activity, If you don't follow it and someone is hurt on your activity, you can be liable.
Here is the policy from the "Guide to Safe Scouting":
The Boy Scouts of America adheres to its longstanding policy of teaching its youth and adult members the safe, responsible, intelligent handling, care, and use of firearms, air rifles, BB guns, and archery equipment in planned, carefully managed, and supervised programs.
Except for law enforcement officers required to carry firearms within their jurisdiction, firearms shall not be brought on camping, hiking, backpacking, or other Scouting activities except those specifically planned for target shooting under the supervision of a currently certified BSA national shooting sports director or National Rifle Association firearms instructor.
All shooting sports activities held during a council resident camp will follow the standards in National Camp Standards, No. 430-056. All shooting sports activities held outside of a council’s resident camp will follow the rules and regulations found in the BSA National Shooting Sports Manual, No. 30931, which can be downloaded here.