They are made for rifled barreled slug shotguns.
These Barnes Vor-Tx 12 Gauge 2.75 in Expander Tipped Shotgun Slug Loads are designed for rifled 12 gauge shotguns and not smooth bore barrels like he KS7.
The Barnes Vor-Tx 12 Gauge 2.75 in Expander Tipped Shotgun Slug Loads could be used with a 12 gauge H&R Ultra Slug.
The Barnes Vor-Tx 12 Gauge 3 in Expander Tipped Shotgun Slug Loads can be found at the link below. However, they are currently unavailable.
https://www.opticsplanet.com/barnes-vor-tx-12-gauge-3-in-expander-tipped-shotgun-slug-loads-5-rounds.html
The Barnes Vor-Tx 12 Gauge 2.75 in Expander Tipped Shotgun Slug Loads can be used in that shotgun as long as the correct choke tube is installed in the barrel.
These Barnes Vor-Tx 12 Gauge 2.75 in Expander Tipped Shotgun Slugs are designed to be fired in 12 gauge shotguns with a rifled barrel or rifled choke tube. So if you have a Mossberg 835 12 gauge with a rifled barrel these Barnes Vor-Tx 12 Gauge 2.75 in Expander Tipped Shotgun Slugs will work.
Yes, these rounds can be used in an indoor range.