After fixing the chamber, will the gun fire

[CINDERS]

One thing I was told that rounds should be fed from the mag as the rim can easily slip under the extractor claw that single loading like that and forcing the claw over the rim can lead to breaking of the claw.
Is this just an old wives tale.

I fls and ttl every firing all my 303 shells bar the ones for the sniper T that has its own brass just neck sized though I anneal the necks every firing with the AMP machine.
I think you may find that could be the divet left from the chisels intervention into the chamber wall not much can be done with that I had one way worse than that from the acvid in an insects body that crept down and died could only extract the cases by belting the bolt open, new barrel time for that one.