On balance, allowing civilians to own guns is detrimental to society

* The outliers are easily explained by independent reasons, such as Estonia's astronomically high poverty rate [13] and Mexico's organized crime problem (which, as will be explained later, is largely fueled by a steady supply of guns from the US).

C2) Suicides

The logic here largely follows that of the first contention. Since the vast majority of suicides are impulsive, it makes sense to assume that many of them would not happen if the means to painlessly kill oneself were not readily available to the victim. A gunshot to the head is one of the easiest, most reliable, and most painless ways to die, which is why, unsurprisingly,  52% of suicides in the United States are committed using a firearm [13]. It logically follows that the absence of guns would make it much more difficult for the average person to commit suicide, thus forcing victims to take more drastic measures and substantially decreasing the likelihood that the victim will actually go through with it. And it shows-- [14]

It's quite safe to say that allowing civilians to own guns significantly increases suicide rates...

C3) Accidental Discharges  

Between 1965 and 2000, approximately 60,000 people in the United States were killed from unintentional firearm shootings [15]. To put that into perspective, that is more than the number of Americans who died in wars during that same time period. The impact of this should be clear-- deaths from accidental discharges are 100% impossible without private civilian ownership of guns, and thus represent yet another considerable toll of allowing civilians to own guns.

C4) Mass-shootings 

In the US, there about 16.4 mass-shootings per year, with 486 people having been killed in such shootings since 2000 [16]. That isn't a very big number; however, like terrorism, the primary harm of mass-shootings is not in the number of deaths, but in the collective psychological effect that such incidents have on a society: “Mass shootings are a marginal concern, even relative to other forms of gun violence, but they cause an unusual degree of terror and grief—particularly when children are targeted. Given the psychological and social costs of certain low-frequency events, it does not seem irrational to allocate disproportionate resources to prevent them… our perception of danger is easily distorted by rare events. Is gun violence increasing in the United States? No. But it certainly seems to be when one recalls recent atrocities in Newtown and Aurora. In fact, the overall rate of violent crime has fallen by 22 percent in the past decade.” [17]. This is confirmed by the results of a survey released by Pew Research Center, which showed that only 10% of Americans feel that gun violence has decreased over recent years. [18].

Guns are not responsible for all incidents of mass-murder, of course, but they undeniably make mass-murder much, much easier. Their long range enables the rapid shooting of multiple people at a time, and the "detachment" effect of shooting a gun allows for mentally unstable people get more satisfaction out of killing than they would from stabbing or setting a fire. Moreover, a mass-shooting is far more likely to end up in numerous deaths (instead of just injuries) than other forms of mass-murder; knives only kill if they hit a vital organ, and most modern buildings have fire escapes. It is simply absurd to claim that in absence of guns, mass-murders would continue occurring at the rate they currently do. The fact is, that incidents of mass-murder do not occur *nearly*  as much around the world as they do in the US [19]. Allowing civilians to own guns greatly increases the frequency of mass-murder incidents, which has a profoundly negative impact on society by making its inhabitants feel less secure.

C5) Injuries

One thing which is commonly overlooked in analyzing the impacts of civilian gun ownership is injuries from firearm violence, which occur far more often than homicides or suicides. According to the CDC, about 84,000 Americans are suffer injuries from firearms every year [20], which has been estimated to cost over 2.3 Billion dollars per year in medical costs [21]. This kind of financial expense is quite detrimental to the welfare of a society, because not only can that money be spent on more productive ends, but National Healthcare and emergency room regulations cause much of the burden of that cost to fall upon tax payers (in the US, it is roughly half of that burden). Following the logic outlined in C1 and C2, we can conclude that many of these injuries would not have happened without the 

I was going to make another argument, but I'm running low on time, so I'll just save it for next round.... 

Spoiler: it's about increasing the risk of civil wars in third world countries.

CONCLUSION: I have shown that allowing civilians to own guns results in a number of highly detrimental costs to society such as causing . It substantially increases homicide and suicide rates by providing the means for relatively minor events (e.g. heated arguments, fist fights, road rage, anxiety attacks, depression, etc.)  to escalate into such fatal occurrences, and it also makes possible death by accidental discharge, which claims a considerable number of lives as well. Furthermore, guns makes mass-shootings-- the most frequent and most common form of mass-murder-- possible, which has a demonstrably negative effect on a society's collective psychology akin to that of international terrorism. Lastly, civilian gun rights result in a massive number of injuries, which has a high financial toll on society.