New collector, need advice please

[browningautorifle]

look for a good gunsmith who can bore it out and sleeve it.

I wouldn't do that...not for a full bore rifle. Using a sub cal insert might be OK, but if you don't like a chamber or barrel, just replace it. Just so LooneyToon understands, I've done it too. I wouldn't do that...if I were you.

Yes, an alteration removes the value.