The guy said I cannot use slugs under any circumstances because the barrel is not rifled
Bravo Sierra. Hope they pay whoever told you that for what he does (like sweeping the floor) instead of what he knows, because if they pay him for what he knows they're wasting their money.
It's OK to shoot rifled slugs through a smoothbore barrel. I'd use a more open choke tube, like ImpCyl for that were I you.
+1 on downloading the owners manual from the Remington website and getting familiar with it.
Any good 2 3/4" load with larger size lead or HeviShot pellets will do for home defense. At close range shotguns cause what surgeons call 'rathole wounds,' and as long as pellets will penetrate deeply enough to reach important anatomical structures they'll work for defensive use. Anything in the neighborhood of #2 or bigger, in other words.
At close range shotguns are almost like shooting rifles- you
can miss with one. Peripheral hits with a shotgun may not stop a drugged or determined intruder- you still have to hit center mass even with a shotgun. Don't assume one shot will do it with any weapon, even a shotgun- run the bolt immediately after the first shot and be ready to shoot again if necessary.
Get in plenty of practice time with the scattergun, it takes some getting used to if it's your first pumpgun. Get into the habit of racking the forearm briskly all the way back till it stops, then all the way forward till it stops in a one-two count movement. That way you'll avoid the most common operator error with pumpguns- short stroking.
You might find that getting another smoothbore factory barrel 18- 20" long will make the shotgun a bit more weildy inside the house. Spare 870 barrels are pretty widely available and not awfully expensive. The most common one around here is a 20" smoothbore with rifle sights, commonly called a slug barrel. It's easy to swap barrels on an 870.
Enjoy it, and Stay Safe,
lpl
