AR used in the shooting was around 800 bucks, from a company called Lead Star Arms. Looks to be a 14.5" with a SB Tactical brace. It is called the Grunt, which is a line of Budget AR-15s the company makes. I was looking them over and holy shit you cannot make this up. Lead Star Arms sells a 17" Grunt with a Trans Flag color scheme that is covered in snowflakes.

https://www.leadstararms.com/grunt-ar-15-rifle-5-56-nato-w-17-handguard-snowfall/

Bodycam footage