"Let me be absolutely clear. The purpose of requiring FFLs to report the specified multiple long gun sales in these four source states is to identify criminal firearms traffickers, not to prevent the full and free exercise of our Second Amendment rights, or to encumber the FFLs with burdensome paperwork."
The fact is, filling out ATF Form 3310.4, Report of Multiple Sale or Other Disposition of Pistols and Revolvers is already a considerable amount of extra work for the FFL. Currently, You can buy a rifle and a shotgun or 3 rifles at one time without filling out any forms for multiple sales. Reporting multiple sales is additional work because unlike form 4473, multiple gun sales have to be additionally reported to Local/State police even in states where this is otherwise not required.