Chris, I do load for my 673. I'm using 220gr Speer Flat Points (because I like Speer and all I had were these Speers and some Sierra 225s. I don't like Sierra much after them being rude to me several times when I called to ask for information, plus the Sierras sucked as far as accuracy is concerned. Best group was the lowest charge of two different powders, and the group was just under 4" at 100yds. With the Speers and BL-C(2) I was able to get my best group at max charge, so I decided that was the way to go. Best group was under 2", but may have been under 1.5" (I'm pretty sure it was, but I don't have it to measure, because I got in a hurry leaving the range and my targets blew off the tailgate and I only found some of them.
I have mine set up with just the open sights as it came from the factory, so it's a small notch rear and the sharkfin front. So 1.5-2" at 100yds, hitting about .5" high, gives me a great short range woods gun, that points well for snap shooting. I bought it to use as a stalking gun, for the drains and draws on our mountain lease. After today's experience, I believe my thinking was absolutely correct. I managed to snap shoot a jogging coyote at over 60yds, through an opening in moderately dense woods, hitting him in the ribcage about 2" below the spine. He nosed over at the shot and never took another step.
I have talked to other folks with these 673s and they've had differing experiences, with the worst offenders requiring action bedding and barrel floating along with a ton of loadwork. I've been lucky with this one, and won't complain. I wanted one of these for a long time - I saw a 300SAUM in about 2005 and wished I'd had the $379 asking price then. I snapped up this 350Rem when it came available via a friend of mine. Picked up some dies and brass from him and a couple other guys, along with a couple "half boxes" of bullets. I've stocked up on the 220s now that they're the choice, and I doubt I'll need any before the next presidential election! I certainly hope you can find one. Keep an eye on gunbroker. Oh, and if you're interested in paying a hefty price, I know where a brand new one sits on a dealer's rack. Or at least, it sat there in November, and had been there since March or April. They're asking something like $800 for it (maybe $750?) but I suspect there's some room to negotiate. Shoot me a PM if you'd like me to check on it. Could do that one day this week, probably.