I linked to this study (also from Harvard) elsewhere in this thread.

International evidence and comparisons have long been offered

as proof of the mantra that more guns mean more deaths and that

fewer guns, therefore, mean fewer deaths. Unfortunately, such

discussions are all too often been afflicted by misconceptions and

factual error and focus on comparisons that are unrepresentative.

It may be useful to begin with a few examples. There is a compound assertion that (a) guns are uniquely available in the United

States compared with other modern developed nations, which is

why (b) the United States has by far the highest murder rate.

Though these assertions have been endlessly repeated, statement

(b) is, in fact, false and statement (a) is substantially so.

Next, they discuss rates of gun ownership and murder in various other countries. The Soviet Union (and then Russia) had virtually no civilian gun ownership, but much higher murder rates than even the United States. For example, Russia's murder rate in 2002 was 20.54 per 100,000. Luxembourg, which has virtually non-existent gun ownership, had a homicide rate of 9 per 100,000 in 2002, which was almost double the U.S.'s rate for that year. They also look within countries, and find that, for example, gun ownership rates correlate negatively with homicide rates across constabularies in England. Quoting research on the efficacy of British gun control measures:

The peacefulness England used to enjoy was not the result of

strict gun laws. When it had no firearms restrictions [nineteenth and early twentieth century] England had little violent crime, while the present extraordinarily stringent gun controls have not stopped the increase in violence or even the increase in armed violence.

Armed crime, never a problem in England, has now become one. Handguns are banned but the Kingdom has millions of illegal firearms. Criminals have no trouble finding them and exhibit a new willingness to use them. In the decade after 1957, the use of guns in serious crime increased a hundredfold.

The authors go on to point out that many studies look at gun laws and how they prevent gun violence but not violence overall. In other words, if a study shows that gun deaths go down after more restrictive laws are put in place but not murder rates as a whole, that shouldn't be used to prove that gun laws are effective in reducing murder rates (but often are).

As for the idea that self-defense uses are rare:

Recent analysis reveals “a great deal of self‐defensive use of firearms” in

the United States, “in fact, more defensive gun uses [by victims]

than crimes committed with firearms."

And

National Institute of Justice surveys among prison inmates

find that large percentages report that their fear that a victim

might be armed deterred them from confrontation crimes.

“[T]he felons most frightened ‘about confronting an armed

victim’ were those from states with the greatest relative

number of privately owned firearms.” Conversely, robbery

is highest in states that most restrict gun ownership.