ronreme said
Thanks for all your comments. The barrel has not been relined, my friend in the north of Ireland threaded the hole in the barrel screwed a threaded plug into the hole. He then tig welded the plug contured it to the shape of barrel, polished by hand and reblued the barrel and receiver and various other parts. the hole in the forearm was pluged and wood was gently refinished. The gun will not be shot as it was purchased as an obsolete calibre firearm, meaning here in the UK it can be owned without a firearms certificate. The gun was aqquired by the auction house from a farmers estate in Cumbria, I presume the farmer not knowing it was obsolete calibre drilled the hole to show people or (police) that it couldn't be fired. Thanks for agreeing that it looks better than it did.
  

What a tragedy, you did a wonderful job and you have a nice wall hanger.   I hope the zombies don’t show up.  There is a documentary about this where a handy functional Winchester was able to save several people.  

I would say congrats on the job you did, especially for saving a rare caliber specimen. Shoot it yet?

Bob

The trigger assembly of the 07 is a reliable design and is used almost intact in both the .30 M1 Carbine and the Model 50/59 shotgun. However, it has a very slight amount of takeup creep. More significantly for our investigation, the trigger does not move at all - no creep - when the crossbolt safety is engaged. 

At the range, when the trigger is pulled on a live round, the trigger does not move. There is no takeup creep. At home, when the trigger is pulled on a dummy round, the trigger takes up very slightly and then "fires" the dummy with an audible firing pin strike on the dead primer. 

The firing pin assembly is not blocked, as can be verified by other means as well. It is the trigger stroke alone that is blocked and there are only two things that can block it:

1. Manual engagement of the crossbolt safety by pushing the button in the trigger guard.

2. Automatic engagement of the crossbolt safety by the "out of battery" lever:  the spring loaded lever installed in the left wall of the lower receiver,  directly over and connected to the crossbolt safety. Under spring pressure this lever is held vertically at full extension and the trigger is blocked. At full extension this lever rides along the bottom of the breech bolt. There is a bulge or block at very end of the bolt, such that when the bolt is in full battery the lever is depressed, unlocking the trigger stroke. 

The rim thickness dimensions of the live and dummy rounds are virtually identical. Both seat fully in the chamber, as can be confirmed visually. The live rounds are Western factory. Insufficient headspace is not an issue.

The most likely reason the trigger is blocked at the range is the failure of the bolt safety lever to be fully depressed, for some reason. 

At the range,  I failed to bring the set of dummy cartridges, to try after the live rounds would not fire.  That would have probably revealed cartridge dimensions aren't the problem. 

I carried the 07 to the range disassembled in a Boyt takedown case. This particular 07 has never been taken down very much and all the steel edges are sharp and unworn. If not lubricated, the upper and lower receiver are difficult to manipulate into position and close fully. The takedown bolt requires a screwdriver to firmly close the two halves. 

I now believe the lower receiver can be installed with enough of a barely noticeable gap that the bolt safety lever is not fully depressed.   The lever is on the lower receiver, along with rest of the fire control mechanism. The breech bolt is in the upper receiver. 

When I came home from the range, it was a couple of days before I cleaned and reassembled the gun. Before I did so, I decided to "season" all the internal steel with BreakFree CLP, to impregnate the pores and make a slick, molecular-level bond. It has made assembly and functioning significantly easier. Of course, after I assembled it and tightened the takedown bolt with a Brownell MagnaTip, it shucked and "fired" dummies without issue. Repeatedly. 

The most likely cause of the trigger lockup is that the internal, spring loaded, bolt-out-of-battery safety lever mounted in the left wall of the lower receiver is not being fully depressed. I can prove or disprove my theory just by bringing dummies and live ammo to the range. "Firing" a dummy and then loading a live round. What I should have done before. 

I am a slow learner and a sloppy investigator.

Somewhere there must be factory literature advising the anticipated round count when the buffer should be replaced. Or at least advising inspection and a minimum size gap.

As Bert said, they aren't noted for target accuracy but a cop, armed with one and a 10-round magazine of metal cased slugs, could deal a Depression Era bootlegger's V8 Ford and its occupants a lot of grief. The 351 round had an appreciably better trajectory than the Thompson's 45 ACP. Having owned and shot the Remington Model 8,  it's more powerful but not as compact or handy.  

A prison guard, faced with a full-on riot, would take comfort from having one in his hands loaded with ten 180 grain softnose rounds. 

The late, unlamented Homer van Meter was of the same opinion,