Rifles are used in about 3% of all gun crimes according to FBI stats. ARs or so called 'assault rifles' make up a tiny percentage of THAT 3% and I dare say that rifles assembled from 80% lowers and 'kits' make up even a smaller fraction of THAT number! Talk about nit picking nitwits.
If they legislate these 80% lowers out of existence it's be akin to 'fighting drunk driving' by banning Volkswagon Passats from US highways.
Are Passat drivers more likely to drive drunk than owners of other makes/models?