Apples and pears
Yes, indeed, firearm related deaths are higher in the US than in the UK. However, the rates are immensely closer when you look at "intentional homicide" instead. That includes all the other weapons around you, including bludgeons, frying pans, poisons - visit the Agatha Christy "poison garden" some time - cars, bare hands, boots, bats (cricket or baseball), and etc. You also fail to mention how many of the UK firearm deaths are instantiated with a legal weapon. The odds are very low that more than a very small fraction are from legal weapons of any kind.