With one lot of Remington Foster-type slugs, my old Ithaca M37 Deerslayer would shoot 3" to 4" groups at 100 yards (had a 2.5X scope on it). With other brands of slugs, it was hopeless or worse! Federals and Winchesters were particularly bad.

A lot depends on what kind of a wad they put under the slug-if is is a thick, stiff card wad that will not enter the base cavity in the slug and deform the slug, the load will shoot a lot better than loads that have soft, easily deformed wads right under the slug. Also good are slugs that have a plastic plug in the slug's base cavity to prevent distortion of the slug as it passes down the bore.

It is important not to have too much choke constriction in a tube you plan to shoot slugs in, and any barrel that has the same inside diameter as the slug's O.D., the better it will shoot THOSE PARTICULAR slugs! (This has nothing to do with safety - a slug will swage down and pass thru any reasonable degree of choke. BUT the more the slugis deformed before leaving the barrel, the worse the accuracy will be.)

A real problem is that no two outfits make slugs the same size around, and even slugs of the same brand can vary a lot in size,weight, and even wad column configuration. That's why it is important that, when you find one particular lot number of a brand of slugs that shootwell in YOUR GUN, you need to buy a case of them!! They may be different next year!