Actually, before and during Bundy Ranch (and even now), BLM stood/stands for The Bureau of Land Management, a Federal Agency that was pulling a lot of crap on landowners out west and those who had grazing rights through leases (and continues to do so, even now).
Black Lives Matter's "BLM" Just happened to be a convenient acronym that surfaced about the same time, and blew the other BLM (and their abuses) off the search engine page. Handy coinkydink, ain't it?
Now, try a google search for the 'number of semi-automatic rifles in the US'.
Yu won't get the number of Johnsons, Garands, M-1 carbines, even Mini-14s or M1As, and no one seems to know just how many AK variants are out there, all you see are AR-15s, a mere 5-10 million (no one seems to know) of the guns.