Weapons are force multipliers that make it easier to kill. The easier it is to do something, the more likely it is that someone will decide to do it.

There are cultural, demographic, population, and other factors that complicate comparing US murder rates to UK murder rates, but for the sake of posterity, the murder rate per 100,000 is

Chicago: 20.7 NYC: 5.5 London: 1.5

But as I said, there are too many factors at play to fairly compare these when it comes to the question of whether making weapons more scarce reduces violent crime. So I'll give the very simple answer that when the UK police are walking around 'randomly' searching brown people for knives, the violent crime rate starts to magically fall.

When the UK police are then prevented from 'randomly' searching brown people for knives because doing so is 'racist', the violent crime rate starts going back up again. This is a repeating pattern that has been going on since the 90's when the diversity started necessitating it.

Generally speaking, you don't go to prison for being found with a knife - so it's not like people are being removed from the equation. The knives are removed (or more accurately, somewhat reduced in number) from the equation, and the violent crime rate falls.

So yes, I am quite certain that reducing access to weapons reduces violent crime. I am also certain that reducing problematic diversity would be far more effective.

I realise the average gun-loving American only wants to face one of those realities, and I completely understand why, but that's no reason to deny the reality. Not for me, at least.