Can i hunt Deer/Boar with a 12 guage?

Regular foster slugs are perfect for deer. Brenneke Black Magic slugs will work on boar or any other North American species. You are probably limited to 50 yards unless you do a lot of practicing or get something better than a bead sight.

Of course you can. Buckshot is called that for a reason. It has been used for many decades in thick forest or brush, and in such areas is often the only legal firearm. You do need the necessary stalking skills to get within effective range of the quarry; ~25 yards is about the maximum effective range of buckshot. Slugs can extend this to about 50 yards before accuracy falls off in a smoothbore barrel. At the shorter ranges and thick cover they hide in, slugs should be devastating on even the toughest old boar. You don't say where you live. If you will be hunting your deer out west, where a shot might be hundreds of yards, you will be better off with the rifle.

it it has screw in chokes,you can get a rifled one the will improve slug accuracy

Check your state hunting laws to see if buckshot is legal. It's not here in NY.

But 12-gauge slugs have been the standard in this state for 100 years or so. Not until recently has most of the state opened up to rifle hunting.

A 12 gauge with slugs is the old standby for deer. I would have no worries if you can practice and be accurate with them. Some are real shoulder breakers!

Stay away from the 770... there are much better choices for the price.

Are you in bare county or brush? Nothing beats a 12 gauge pumpkin in the brush! Shoot, I wouldn't want someone to throw a slug at me by hand, that allot of lead!

All but one of my deer were shot inside 25 yards... It depends on where you are hunting, a slug may be the top choice for you.

All of the 590's I'm aware of are cylinder bore and do not have interchangeable chokes. At close range slugs would work. Accuracy could be tricky. Some 590's have a bead front sight, others have rifle sights. If yours has rifle sights it should be good for around 100 yards. With a bead, maybe half that.

Buckshot is a good close range SD load, but I would only use it for hunting at very close range.(actually I wouldn't use it) It is not legal in a lot of places because it wounds a lot of deer etc. that will eventually die and not be recovered.

Most shotguns are not ideal, but if it is all I had it would not stop me from hunting. That is the way I started before I could afford a rifle.

A 12 gauge 1 oz slug is big medicine for deer and I don't imagine there is much in North America that it couldn't dispatch if the shooter does his/her part

Be careful using buckshot for deer hunting. I live in a state where buckshot is illegal for deer hunting. However you can shoot relatively accurate out to 100 yards with a shotgun. You should be able to put 80% into a paper plate at 100 yards with a little practice. A shotgun can take any animal in North America including Grizz or Moose, so I would think that it would handle Boar and Deer. Good Luck with your hunting!

Also being in California make sure if you are in a lead-free "Condor" zone that you use lead free buckshot or slugs.

Just my .02,
LeonCarr

Rifled or sabot slug, your choice. Standard "rifled" slug for smoothbores...choke don't much matter but IC and MOD seem to do best, sabot for rifled barrels. Heck, when you're tossing out close to 2K foot pounds of energy in an almost 3/4" diameter bullet a little hog won't give you much trouble. Biggest problem is getting the gun sighted in to hit where you want.
Last time out I used a Remington rifled barrel 870 with Nobel Strike slugs. 180 pound deer, pass through with a good one inch wound channel. No, didn't find the slug. It is somewhere in my north 40.

You can hunt anything you like with a shotgun. Whether you can get close enough to hit it is the only question. (As some wag remarked, it's called "hunting" for a reason.)

Still, a pal of mine has scored antelopes on the American plains with a bow and arrow, with much less effective range to work with, so patience, persistence and catchem-savvy are more important than equipment.

If you are shooting slugs, use a sight, of some kind that is more precise than squinting at the bead. If your 590 has the ghost ring setup on it already, you're good to go.