SMLE Chambering round issue (pictures) Help!

[marksman]

you don't need a rebarrel just rechamber, probably cost around $120 I think, that's how I would go as well, then you can buy factory ammo
you are covered by consumer law but I really think there is a mistake nothing deliberate
all will be good

[bladeracer]

Sounds like the shop had no idea.I would keep it the way it is and make ammo for it.good bit of history

I agree, the fact that these were done is part of the .303 history. I would enjoy it for what it is.

[vietboy]

I remember this calibre.

New South Wales has always had a law banning military calibres, presumably so ex soldiers wouldn't steal their issued weapon when demobbed.

The easiest conversion for the SMLE was to cut 2mm from the barrel end and modify the extractor slightly.
The cartridge was close to .303 so I guess it was easy for factories to retool.
The rifle won't fit a .303 cartridge but the modified calibre is called 7.7x54, somewhat confusing because I believe there is a Russian calibre with the same name.
It is quite naughty if they didn't mark the modified barrel. It could have been a home made job because it was an easy modification. Ammunition was readily available in Australia through the 1960s. However the only ammunition I have used was rubbish, mostly misfires.

[GojiraSteve]

I wonder if it had sat in the previous owners safe for years completely shot out until he came across a dirt cheap barrel and had "tarted it up" for sale. Never realising why the new barrel was so cheap.
Between the previous owner, the gunsmith (assuming it's not a backyard rebarrel job) and the dealer you'd think someone would have spotted it though.

[Diamond Jim]

Does the bore measure about .311" at the muzzle?

Yes, check this - can you run a .303 jig down the bore? Are you using new factory ammunition (i.e. not reloads fired in another gun). Is the chamber clean? Can you see any imperfections or damage in the chamber? Is there anything stuck in the chamber (most case separations occur at the base so this is unlikely - could be a stuck projectile? Just thinking but the gun store should have checked all of this).

If you tick all the boxes take it back to the store and demand a fix or a refund.