The Brandeis Brief established the model of compiling statistics to prove the argument: that is, the use of non-legal data as a valid secondary authority.
The article at the link below provides evidence of the vast common use of the basic AR-pattern rifle which typifies the so-called Modern Sporting Rifle. Since 1990, domestic production of AR-pattern rifles totals 28,144,000. Its flexible design allows use in most fields of sport shooting and defense applications. In the realm of both Action and Service Rifle competitive shooting, you either shoot an AR or you get beat by someone who is. This is an interesting fact to consider in light of those claiming these rifles are “useless” for target shooting.
The U.S. government data on AR-pattern rifle production and use are exactly what Bruen requires the government to defeat in efforts to restrict ownership and use of any firearm. Likewise, when anti-gun legislation is proposed, proponents need to know they are promoting unconstitutional law and arguably a violation of their oaths of office.
https://journals.law.harvard.edu/jlpp/the-relevance-of-in-common-use-after-bruen-jamie-g-mcwilliam/
Transcript and citations:
Some commenters have stated the clip with Eugene Stoner seems ambiguous as Stoner doesn’t specifically address which designs he intended for which markets. That's the point! If a given design (AR-10/AR-15) was only for military sales, he never stated it. Articles making the claim the AR-15 was supposedly military only quote his family as saying, “ArmaLite was seeking military sales for the design” (which is true) but then jumped to a conclusion by claiming this meant the design was ONLY intended for military sales even though it had been released to the civilian market before the military officially adopted it. Also, Stoner's and ArmaLite's intentions - stated or otherwise - do not change the Constitution or federal law regarding firearm ownership.
This common use of rifles based on the AR-15 and military counterparts, the M16/M4 series, is nothing more than the trend of shooters making use of firearms similar to what is in common use with the military. Before self-loading rifles were commonly issued, surplus bolt action rifles were most popular. The Department of Civilian Marksmanship sold surplus military rifles to American citizens and mailed them directly to their homes for many decades, a practice that continues with the Civilian Marksmanship Program. Retailers also had firearms available for purchase by mail for direct purchase with no restriction.
Thanks to John Tate for the info on this!