Best container to move prized records between homes? Thanks!

These are all being moved professionally by truck, 1,800 miles across country.
Past experience has been hit or miss that the professional movers pack safely.

Thank you everyone for your helpful thoughts, both past and if there are any in future.  All very much appreciated!  Enjoy your music!  

I ended up using U-Haul "book boxes." I packed all the LPs myself, adding a thin polystyrene foam board each end, and using lots and lots of strong packing tape. 

The LP's fit very snuggly, at a slight angle, so left a very small 'triangle' space at each end .  These end 'buffer' zones were filled with air bags/peanuts/foam bits. 

I also ensured my item specific insurance was up to date. 

Finally I personally oversaw the movers doing 90% of the moving, loading and unloading.  Toughest part was training them to very carefully but briefly use their dolly cart with boxes four (4) high, to move from the house to the truck.  The boxes were only placed two (2) high in the truck, with nothing else on top.  All of the boxes were very carefully handled from what I saw.

All the records arrived fine so thanks again guys!  Phew!