Thanks everyone!
That length info is very much appreciated!

I'm very much a rule follower... these guns are super important to me, so I dont want to risk any issues.

It seems that there are no "TSA Approved" gun transport cases..
Just the spec that they are hard sided, pry proof and lockable.

Virgin Atlantic rules for traveling with "Sporting equipment", says...

As you might imagine, we have a few rules surrounding firearms.

As part of your baggage allowance you can check in as many firearms as you’d like, provided you have the correct paperwork to confirm you’re allowed to own each item.
You’ll also need paperwork demonstrating you are allowed to import, export and own each item within the countries your trip will take you to.

Excess baggage charges will apply should you exceed your baggage allowance (details of fees are on our additional baggage page).

Exceptions

If you’re travelling to the US, Shanghai or South Africa, there are additional considerations. Please check below for further details.

What we consider a firearm to be:

For clarity, we define a firearm as anything that fires a projectile – whether it uses air, string or explosives to do so. This includes items such as:

Sporting rifles
Pellet guns
Crossbows
Antique weapons (these must be decommissioned, so they are no longer able to fire).

Virgin Atlantic has Home Office permission to carry handguns classified under section 5 of the Dangerous Weapons Act. As with sporting firearms, you must have the appropriate documentation for both ownership and carriage of these items.

Ammunition

We define the following items as ammunition:

Lead pellets
Arrows
Crossbow bolts
Bullets.

Note that all firearms must be empty when you pack them. Ammunition must be packed separately from firearms in its original packaging and locked in a solid case.

Ammunition is limited to 5kgs per passenger, in line with IATA Dangerous Goods Regulations, and cannot be pooled with other passengers.

Any ammunition containing explosive bullets, toxins or incendiary projectiles will not be accepted on our flights in any circumstances.


I've identified a case made by Apache, the 5800, that is available here from Harbor Freight, for $99.

https://www.harborfreight.com/5800-w...rge-64819.html

Looks to be about 22" x 14" x 9".

I'm thinking I'll buy the case here, take all the foam out, and travel to the UK with it filled with my clothes, and personal stuff, plus a folded duffel bag inside.
Then, break the rifles down, separating the barrels, lever arm, and spring mechanism(Whats that part called?), and those part can go into the Hard case with some bubble wrap, clothes etc..
I gather from the Virgin Atlantic website, that i have to inform them 72hrs in advance, what I am traveling with, and pay an additional 65 gbp fee...
The two bare wooden stocks. can be wrapped and protected, then wrapped in clothes and go in the Duffle bag...