I would probably hold to inside of 100 yards until you get used to it, and practice a bunch. Your shooting style, and your resultant ammo selection will "dictate" to you how far YOUR effective range is, with your gun, and your chosen ammo. If you can keep all your shots on a paper plate, from a field position, I would say you can effectively take a deer at that same distance.
For factory ammo, you may have to try a few different loads to find one it likes. I've only fired 2 factory loads from mine. Both were given to me, one was an old box of Sears "Ted Williams" ammo, and the other was the standard Remington green and yellow core locks. Neither one of those loads shot very well for me, both went over 2"s @ 100 yards, if I recall, and that was shot from a solid bench rest with a variable power scoped barrel.
If I hadn't already known what the barrel was capable of accuracy wise, I would have been greatly discouraged. My barrel prefers the 150 gr Sierra gamekings and the 150 Nosler ballistic tips to the 125's. It will shoot both of those bullets into ragged hole groups from the bench. I say that to give you the comparison test of various loads, and the possibility that you may see some large differences in group size.
If I was saddled with having to buy factory ammo, I think today I would go out and try the new Hornady leverrevolution ammo. I've never fired any of it, in any caliber. But, I hear far too many good reports about it all over the place not to take it seriously.
