If you are going for a dedicated slug gun I woudln't get a pump. I would go for a H&R ultra or a savage bolt action. And for slugs the 20 ga guns are getting lots of good press. They have some very good loads that are matched well to the rifle twists in the guns. Plenty of range and power to take deer past 100 yards. And I think they will have the accuracy advantage, at the very least they may be easier to find a load that they like.

If I had it to do over I would have went with a 20 ga. Very close to the same performane, but a lighter gun with less recoil. Most of the loads out now are very simular to what you would use in an inline muzzle loader, and I really like my ML for performance.

If you are stuck on a pump in 12 ga I would say go with a browning BPS. It's not just a fine gun, both in looks and design, but it has better twist rates with the fully rifled barrels than remington and mossberg do. Nothing wrong with those guns though, especially for the money. You can get some decent combo models that come with a rifled barrel and bird barrel.

My personal opinion though is if you want a dedicated slug gun don't get a pump, get a single shot or a bolt action. They tend to be more accurate by design and handle recoil better. Unless you are talking about a deer slayer, but I don't think that is in your price range.

If you have an incling in your mind about scoping this gun and get a pump go with the cantilever barrel. This lets you mount the scope right to the barrel, not the reciever. Much more convenient and accurate then mounting a scope the reciever of a gun with a removable barrel. And the H&R and savage both are made to have scopes mounted to them.

If price is a concern my hands down pick is the H&R Ultra Delux in 20 ga. This would leave you money left over for mounts and a decent scope. If you not stuck on the 500 dollar limit I would get the savage bolt action. It costs a bit more but it's a nicer gun.

Those are my opinions, do with them what you will.

Another consideration is getting a good inline muzzle loader, this would also extend your hunting season for you. I hunted for three years just using my remington 700 ML. It worked very well for me. The only reason I got a shotgun was because I was lazy and didn't want to fuss with the ML anymore (cleaning, sighting in, loading). Performance wise it is still better than my shotgun in range and accuracy.

Good luck,

Paul

P.S. Don't be afriad to hit the used gun racks, I bought my H&R ultra used for 100 bucks less than it would have cost me new. And I got a A5 Stalker that looks like brand new but was made in 92.