The ATF's interest in so called "tactical" shotguns goes back to 1984. In 1984 the ATF invoked the "sporting purposes" clause of the GCA of 1968 to ban the import of a shotgun. This was the first time the "sporting purposes" clause was applied to a long gun.
In 1984, the "sporting purposes" test was specifically applied to rifles and shotguns. The firearm in question was a South African riot control shotgun. The importer, pursuant to the statute requirements, indicated that the weapon fit "sporting purposes" due to its "suitability for police/combat style competitions." ATF denied the license.
Two years later, a second shotgun application was denied due to the firearm not being "generally recognized as particularly suitable for or readily adaptable to a sporting purpose." Here, ATF clarified that firearms must attain "general recognition as having a sporting purpose" and events must attain "general recognition as being a sport."