All your links are misleading. I have no doubt that the percentage of black people buying guns is increasing, but compared to the gun nuts that are driving most gun sales, that increased percentage still results in a very small number of guns. The gun nuts that are buying most of the guns now are the same ones who have been buying most of the guns for several years. Siting percentage increases in this case makes no more sense than siting gun crime percentage increases in places like England, which still has a tiny amount of gun crime compared to the US.
When considering that the items being bought most represent what could be considered "introductory" weapons and ammo, your logic is faulty.
A lot of the cheapest and simplest pistols are being bought like hotcakes, and collectors (the people you call "gun nuts") don't tend to buy those. Ammo sales are similar. 9mm is through the roof, and that's one of the most commonly used types for the "introductory" weapons I'm referring to.
What we're seeing right now is a historic rise in first time gun buyers.