In 2020, there were 45,222 deaths as a result of firearms.
53.7% were suicides – self-inflicted death by firearms is the most effective of any method, with a case fatality rate of 82.5%.
42.8% of deaths by firearms were due to homicide
The remaining 3.5% of deaths were accidental, police related, or undetermined
59% of US gun murders and non-negligent manslaughters were attributable to handguns. 1% involved shotguns, and 3% involved rifles that included assault weapons.

According to one study by the Bureau of Alcohol, Tobacco, Firearms, and Explosive (ATF) in 2000 looked at trafficked, illegal gun purchases.
41.3% were straw purchases from federally licensed dealers. A straw purchase is where “those who buy a gun, complete required paperwork, and undergo a background check on behalf of another, prohibited, person. They are illegal transactions concerning firearms.
27.3% were unlicensed sellers
17.7% were Illegally diverted by licensed dealers (6.3%), gun show sales (7.1%), and secondary markets (4.3%)
22.5% were stolen from dealers, residencies, and common carriers
The percentages do not reflect the number of guns trafficked [explain]. In terms of the number of firearms trafficked, the majority, 70%, consisted of
straw purchases 21%
illegal diversion by licensed dealers (including pawn brokers) 31%
gun show sales 17%.

A 2016 report of prisoners in both state and federal penitentiaries by the US Department of Justice on firearms used in the commission of a crime concluded:
6% were stolen
7% were found at the scene of the crime
43% obtained them off the street
25% got them from a family member or friend
7% had been purchased under “their own name from a licensed firearms dealer.”