> white teenager can and does walk down high street carrying a loaded shotgun.
If he walked into Walmart or any public building with it he would have been arrested.
> Black 22-year old at Walmart chatting on the phone while picking up a BB gun off the shelf in the toy gun section, gets the cops called in on him, he says 'it's not real' and they shoot him dead.
Not quite.
The 22 year old removed this Crosman MK 177 air pump rifle from all of its packaging and walked around the store with it. He was ordered to put it down and when he did not comply he was shot.
In the UK an air rifle with more than 12 Foot-Pounds of power is classified as a firearm and needs a firearms certificate to own. The Crosman MK 177 is 12.5 Foot Pounds and has a muzzle velocity of 750 feet per second.