Since Oregon requires it to be an exposed hammer and a exposed cap I believe, I would go with a Thomsom Center Hawkin, CVA replica, or a Cabela's replica in .50 caliber.  Out of these I would shoot the T/C maxi-ball or the T/C maxi-hunter.   With one of those you should be all set with practice.  As far as powders I use Pyrodex and just follow your load tables with the owners manual.  You will also find out that usually the best load will be below the maximum for that caliber. 

thank you for the reply, I will look into the T/C and others you suggest.

I should of added that you will also need a powder flask, powder measure, and a ball starter.  Black pwoder is measured by volum and not weight so you do not need a scale.  The ball starter will make it a lot easier to get what ever you start to stuff down the barrel easier.  If you look online at the ones from Cabela's they offer a starter kit witch includes everything except for powder and caps to fire the rifle.  Also black powder or its replacement is very dirty.  Usually to clean mine I'll take a bucket and put a couple of cups of Pinesol into some boiling water.  Then put the nipple end of the barrel down into this solution and with a tight fitting patch to run it throught the barrel.  The patch will create a suction witch will pull the water/Pinesol into the barrel to clean it.  Then I do it with some clean boiling water to rinse it out, the hotter the better.  I'll then wipe everything down with some T/C Bore Butter 1000. 

thanks again critter, i have a bit to learn

Watch out for the Cabela's replica percussion side lock.  A friend has one, used for several years & was never happy with it.  Didn't care for the open sights it came with (neither did I) the wedge pin that holds the barrel to the stock was a loose fit that kept working itself out while wandering around & it never shot as accurately as he wanted & he's not into target groups - minute of deer is ok with him.  He's since gone to the dard side; went & got himself a TC Triumph inline knowing that he can't use it in some states.

I've been shooting a TC Renegade for years & love it but I don't think they're being made any more.  Dad's got two TC Hawkens, .50 & .54 & has never had reason to complain.  Lyman makes the Great Plains rifle.  Great gun but dresses out at around 10 lbs loaded.  They also make a carbine version (called the Deer Stalker I think) that looks interesting.  It's also has a quicker rifling to accomodate bullets (please, no Sabots) better.

Good luck, plan on 100 yard max distances & have fun!  The learning curve for traditional muzzleloading isn't that difficult & can be addictive.

I hear you about the Cabela's rifle.  Never could figure out why he didn't take it back.  Cabela's has always been good about returns.  I haven't poured lead into a mold since my round ball/rondezvous days so don't know of any molds for maxi's.  Get a recent Dixie Gun Works catalog.  It's got everything in it.  Numbnutz, you should also order the Dixie catalog.  Best 5 or 6 bucks you'll ever spend.  Even if you never order anything out of it, the wealth of muzzleloader/black powder information & trivia in it will keep you up late at night like you were a kid with the latest Outdoor Life magazine in hand. 

I would love to hunt there! I would look for a used T/C Big Bore .58 and use round ball. Yes, I am biased, but I have shot more deer with a .570 round ball than anything else. The balls are readily available and inexpensive ($10 for 50). Recently I have been using a conical and it is a good load, but I am thinking about going back.

FYI - The above advice is sound. A .50 will do the job nicely, I have taken a few with them as well, but I personally believe that, with your state restrictions, a .58 is a superior choice. 

Have fun! 

Thanks for all the usefull info guys, I'm really looking forward to getting started. I'll have to wait just a little longer like after this season.

I'd suggest picking up a book by Sam Fadala.  In addition to an idiot's step by step how to guide with pictures there's also pictures and loads for most common muzzleloaders.  Mine was pretty well read before I even got my first percussion, and I still refer to it occassionally.  I found it covered the basics and gave me confidence, then I asked my specific questions and got well informed answers mostly on this site.

Best of luck, you'll find it's just plain a heck of a lot of fun, and a real challenge, too.  I'm going to try for a doe mule locally in Nov. with mine.