Deactivated Mk1 Bren LMG

The markings on your WW2 Mk 1 Bren gun indicate a fascinating service history involving British manufacture and Australian military use, likely after a factory rebuild or repair. 

Here is a breakdown of the specific markings you mentioned:

"ED" Marking: This mark indicates the original manufacturer was the Royal Small Arms Factory (RSAF) Enfield in the United Kingdom. The name "Bren" itself is an acronym combining the first letters of Brno (Czech Republic, where the original design was made) and Enfield.

"1942" Date: This is the year of manufacture or the year it underwent a significant refit/inspection.

"U5570" Serial Number: The "U" prefix in the serial number typically indicates a UK origin weapon. The full number "U5570" is the unique serial identifier for the receiver body of the gun at one point in its life.

"X" on the butt: An "X" mark on military firearms often relates to an inspection or repair process. On some rifles, an "X" on the receiver indicated that rust had been found and treated, and the weapon needed monitoring. On the butt, it might signify a specific repair, modification, or even a rack number that was cancelled or replaced.

"Cross Sword Stamps": These are likely a type of military acceptance or proof mark. While the "Cross of Saint James" or "cross sword" symbol exists in general history, in a military context, crossed swords/sabre stamps typically indicate a final inspection, acceptance into service, or a proof test mark, varying by the specific nation's ordnance system.

"Australian Army Tag": This is a key piece of information. The tag, in conjunction with other potential Australian markings like the broad arrow in a 'D' (D^D) or an "MA" (Maribyrnong Arsenal) stamp, confirms the weapon was issued to or refurbished for the Australian Army. Many Enfield and Inglis-made Brens were sent to Australia during and after the war. 

Your Bren gun is a well-traveled piece of history, starting its life in a British factory in 1942 and later serving with Australian forces, evidenced by its various markings. The markings on your Bren gun indicate a specific history:

Strippable, dry fires, matching seral numbers.
Comes with Magazine box with 11 Magazines, Cleaning kit.
With Deactivation Certificate