l have flown with ammo in checked baggage many times since 9/11.. Rules are 5 kilos or 11 pounds. l was told by airlines that ammo should be in factory packaging. lt may vary with each carrier. 11 pounds is app 175rds of 22-250, 350 for 223Rem, 400 in 222Rem, and 500rds of 221Furball.. Most BANG for my 11 pounds was a 1000rds of 17HMR for a Ground Squirrel shoot near Goose Lake, Oregon on the Cali/Ore border.
For extra firearms safety l would remove the bolt from my rifle and pack it separately. l also would carry an almost spent roll of duct tape with me.. Right after Security examined my gun and case l would run some duct tape around each end of the case. Told them it was extra precaution to keep case closed during the trip... Also would let ME KNOW if someone had tampered with my gun and case. l highly recommend SKB gun cases... Never a problem with mine.. Enjoy and be Safe.