link to original reddit post by /u/PitaJ
I looked up knife crime stats for London.
London recorded the highest rate of 179 offences involving a knife per 100,000 population 2Fin 2019/20
Assuming that's for 24 months and London has a population of 8.9 million.
179 * 8,900,000 / 100,000 / 24 = 663 knife crimes / month
Source: https://commonslibrary.parliament.uk/research-briefings/sn04304/
In 2017, all rifles accounted for just 403 deaths in the US.
In fact rifles would have to kill 60% more people per year since 2017 to close the gap.