I've bought all mine from ehobby, one package got inspected and sent through.
If your making a shotgun, then a 20" barrel would make a difference, but any standard 40mm launcher length barrels won't make a difference (that was the point I was making)
If you just want to make a realistic shotgun, airsoftsurgeon makes buckshot and slugshot shells you could use as an alternative.
But I have to admit, even I thought of making a 40mm pump action shotgun....
http://www.redwolfairsoft.com/redwol...gshot_5pcs.htm