What kind of accuracy can I expect out of a Remington 870 12 gauge shotgun with slugs?

[Outdoorman]

I would be getting a 20 inch improved cylinder slug barrel with the rifle sights and it is a smoothbore, I may add a scope mount and a shotgun slug scope also.

What kind of slugs would you folks recommend using and what would be a safe distance for taking deer with it?

[Ol` Joe]

I would be getting a 20 inch improved cylinder slug barrel with the rifle sights and it is a smoothbore, I may add a scope mount and a shotgun slug scope also.

What kind of slugs would you folks recommend using and what would be a safe distance for taking deer with it?

Depending on the barrel, slugs used, rest and shooter I’d guess anywhere from 3”/6” at 50 yds is normal.
A good shooter with a good barrel that fits tight with a slug that the gun likes, off a good steady rest should be able to do that at 100 yds. Slugs are like 22lr shells, accuracy can vary by not only brand but lot and often does. Scopes need a good mount, I much prefer a cantilevered barrel over a receiver mount and everything needs to be tight.
Keep in mind too wind affects slugs almost as bad as it does 22lr bullets. A 10 mph wind will cause about 10” of drift @ 100 yds shooting a conventional rifled slug. A sabot slug will drift about 1/2 that. After 100yds drop and drift increases fast and making shots on game after 150yds is more luck then anything JMHO.
I’m sure there are others that have totally different thoughts on most of this

[Rasher]

Slugs ?? Hard to say every gun, every shooter is different, what works for me might not work for you, all lead slugs take a fair amount more cleaning, as they do leave lead behind, how much depends on the brand, Personally I would spend the extra money and get a rifled cantilevered scope barrel, which opens your choices even more. And just fyi, recoil is on the brutal side, I have. 3.5” capable auto loader, and shooting slugs thru it just plain hurts. I ended up getting a lead sled for it.

[Moleman-]

As others have said it really depends on your barrel, slug choice and how good you can shoot. My buddy has a 870 and a 500 smooth bore barrels that both shoot close enough for the slugs to almost be touching at 100yds. My first slug barrel was for an 1100 that was lucky to do 4"-5" at 50yds. Replaced it with a rifled hastings slug barrel that would shoot old win sabot slugs close enough they touched at 100yds. Was stupid and sold it when I was mainly rifle hunting. Got a new Rem cantilever barrel that the best I could get out of it was 4". The scope would visibly vibrate for a second or two after each shot which was disconcerting Replaced it with one of the older made Rem pistol scope/cantilever mount and put a burris pistol scope on it. I've only shot the foster type slugs out of it because the DNR started allowing straight walled cartridges. But with the foster type slugs it was shooting them good enough that they were either touching or almost touching which brings me to another point. If you find a barrel that shoots good for you, keep it.

[john.41]

Most smooth bore slug guns should shoot 9" paper plate at 100 yds. Start with Winchester (silver box) fosters, and a couple boxes of Brenneke's. These were the most accurate in my Mossberg and Remington SB Slug guns.

[jackstan]

I've found the Brenneke the most accurate in my smooth bore .

Jack