Let's see for murder maybe four or five, for violating the gun laws, probably twenty. You have view the violations from the perspective of degree of severity.
I hope you are being funny.
Murder gets anywhere from 10-whole life tariff in the UK. Average probably about 15 yrs, which is far too little and most UK people want it to be 20-30 yrs.
The likes of child murder still gets 20+ yrs. Many UK child killers are on 30-50yr sentences. Or whole life.