A friend of mine bought a later .243 99A just recently. He refinished the stock, reblued it (cold) and tried it out. Keyholes every which way.
After much fooferaw, he found out it was professionally rebored to .260, and it shoots pretty good.
Whoever rebored it neglected to re-mark the barrel, which the rollmark said was .243.
It looks pretty good now, and I suspect that after he tinkers a bit more with it, it's gonna kill a doe or two this fall.
He's got a lot of time and aggravation in it, he might as well get some use out of it.
http://www.missouriwhitetails.com/forums/showthread.php?t=208097