How high is up, Nova? There's all levels of slug performance, with the common denominator being all work fine with good placement.
FWIW, I've two slug shooters in my 870s. They're set up alike, with peep sights, good triggers, mag extensions, and lots of slug testing. The chokeless older one puts the best slug into less than 5" at 100 yards edge to edge, the one with a rifled choke tube more than 4" ETE.
My slipshod records shows these have accounted for maybe 10 deer in the last decade, with more taken by other means.
My all time best buck was taken with a Mossberg bolt action, also a good choice.
One thing, a dedicated 12 ga slug RIFLE is a fine tool for its specialized mission, but loses versatility.
The Archives have tons of stuff on this, get another cup of coffee, settle back and research....