I make my rifle crates out of 1X4 pine with 1/4" plywood on top an bottom. I wrap the rifle in bubble wrap about two layers. Stuff the rest of the open area with crushed newspaper.
I take the lock out of the rifle and bag it seperately inside the crate with the side bolts.
Take it to the post office and tell them I'm sending gun parts, since the lock is not in the rifle, technically it is not a fully assembled rifle. Costs me about $30 -$50 depending on the insurance. It goes Ground.
Never had a hassle or any damage issues in the last 10 years.
Hoot AL
