How can you tell if your shotgun has a barrel that you can shoot slugs through?
I thought about playing around with my 590 to shoot hogs
I have rifles, but thought it might be interesting to try my 12 gauge, just for a change of pace

Can shot slug threw smooth bore, people done it here (Mn) for years deer hunten, & shot slugs threw me 410 hog hunten, just not as accurate. Son bought a rifle barrel for his mosburg 12ga for roughly $100.00.
Edit: RattlesnakeDan all about the choke.

As long as it is not "full choke" I think you are ok. Some barrels are not very accurate with slugs tho so need to shoot some to find out.

Smooth bore shotguns require use of foster style rifled slugs. Rifled barreled shotguns require sabot style slugs. Both require rifle sights or a scope for reasonable accuracy.
As said previously, full choke shotguns are not recommended for shooting rifled slugs. Most slug guns have an open cylinder bore.

You best use a barrel without any choke, Cylinder or open choke unless it's made for slugs such as rifled

The 590 was designed as a combat shotgun so it will definitely shoot slugs. As Pappybear said, foster slugs for smoothbores and sabots for rifled barrels.

For purposes of discussion, anyone able to share the expected range of a Foster slug fired from a smooth bore barrel as compared to a sabot through a rifled barrel? I seem to remember reading that a rifled sabot can easily reach a 100 yard target with plenty of accuracy. Not sure how much drop would result however.

I neck shot a small buck moving at about 60 yards with a smooth bore Mossberg 500 IC barrel.

I am not trying to one up anyone, just giving the info.

TD, the benchmark for most smoothbore shotguns with rifled sights or scope is a 3” group at 75 yds.
I have a Remington 870 Deermaster smoothbore that will reliably give me 3” group at 100 yds.using Brenneke 2 3/4” slugs.
Saboted slugs fired from rifled barrels are capable of 3” groups at 150 yds.or more.
Performances from one shotgun barrel to the next in smoothbore s can be very different. The same goes with different manufacturers and sizes of slugs.

I grew up in Illinois, where it is shotgun only for deer. I used a bolt action Marlin with a fully rifled barrel and scope. I never measured groups, but could reliably hit a beer can at 100 yards. I would sight in dead on at 100 and just hold where I wanted to hit out to about 125. Past that, it dropped like a rock. We would play around shooting 200 yard targets, but it was basically artillery calculations.