Best container to move prized records between homes? Thanks!

Are you moving them yourself in your own vehicle? Not the "best", but the cheapest is the U-Haul small boxes (16-3/8" x 12-5/8" x 12-5/8"). I’ve moved multiple times with those and had no issues.

I added bubblewrap and extra cardboard pieces on the ends and top for additional protection.

I’ve also used the Ultra Box plastic corrugated boxes from Bags Unlimited, but those are overpriced and don’t seem to provide much additional support.

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.

When I moved across the ocean, I personally, carefully packed my LPs in cardboard boxes supplemented with LP sized cardboard inserts. I packed the LPs tightly, hoping that it would minimize warping caused by the boxes perhaps being left in the sun as they steamed their way westward to the tropics. In any event, 90% of my LPs went through the gauntlet unscathed, with only a few developing edge warps. If any were rained on, I honestly can't tell.

I bought a pallet of boxes double walled from Bags Unlimited to have about 5,000 records moved across the country. I packed them myself, made sure that the riders on my insurance were up to date value (a blanket for the records) and the movers handled them fine. They went into a high value vault with HVAC at the mover's facility until we bought a house in our new location.

I subsequently found a better box, cheaper, on Amazon- same deal- double walled, sturdy.

Keep in mind that the insurance attached to the standard mover's agreement is pretty much worthless. (Not that insurance would make it easy to replace some of these things but it is certainly better than a loss).

I used milk crates and a van

I used standard small heavy duty moving boxes and moved them in a UHaul. 95% of furnishings professionally moved.  Then again, I drove 1500 miles without stopping to sleep.

U-Haul Boxes either regular or heavy duty.  Each record size box will hold about 100 LPs.  Then then are HEAVY.  I would suggest you use a pallet.  You will be able to fit 12 boxes per pallet.  Wrap with cling wrap and short of the truck crashing and burning, you should be 100% protected.  

The Classic is Orange crates. You can get them free from your local supermarket. 

Last time I shifted a large record collection I had double walled cardboard boxes custom made cost was not much more than regular boxes.

Trick was to keep the boxes smaller in terms of numbers of records so that they are easy to lift and additional rigidity when stacked.

Successfully moved across country on pallet with no issues ( shipped as top stow only - nothing on top ). You can get pallet crates if you cannot trust your shipper to not stack anything on top.

I've used Per Madsen racks for decades. Additional benefit is they can be moved without taking lps out and transferred to another container. Expensive but very satisfying.

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!

When I moved a year ago, I had to pack my 3000 records so they would survive two moves, first from our old house to a storage warehouse while our new house was being finished, and then 3 months later from the warehouse to the new house 160 mikes away.  I packed them myself using about 35 cardboard boxes purchased from the moving company.  These were labeled book storage boxes and were about the same size as the U-Haul boxes described by others.  Fortunately the moving company had a good number of used boxes they sold me for $1 each.  They had been used a few months earlier to store books when a library was being renovated.  Somewhat to my surprise, the boxes looked almost exactly the same when they were delivered after two moves and three months in storage.  And the records were exactly the same as when packed.  Maybe I was just lucky.

I did not trust the moving company with my equipment though.  I moved everything in a U-Haul truck to a rental storage unit where it stayed until the new house was ready.  That was a lot of work but it all worked out well.