One thing Ive used to counter the addition of suicides by firearm is that Japan has virtually no access to guns and has a much higher rate of suicide than the US.
I don't think it is a good idea to use data from, or about other countries in a debate or discussion about US gun control.
Primarily because the data isn''t relative to the US, especially the way the anti's wish to assume it is.
Other countries are simply, NOT US. Laws, language, customs, history, social pressures and moral guidelines are DIFFERENT. Different from each other, and different from US.
Another reason not to use "facts" from other nations in our gun control debate is that some other nations have been "caught" cooking their books to give a politically desired result. They do this by having different reporting standards, or changing the reporting standards for certain crimes.
Some years ago, I heard that Japan had finally changed their policy about a certain crime. (and since I cannot verify or provide a source, I offer this as hearsay, not verified fact, something to consider, not hard proof)
Seems the Japanese had a category of murder that was, for many, many years not counted as a crime in their criminal statistics reports.
Apparently a cultural thing. And it happened so often it was considered "normal" and not criminal behavior. An overstressed head of household snaps, and kills his family, then himself (nearly always with an edged weapon, knife, sword, etc.) For a long time, this wasn't considered "murder" and didn't go into the murder statistics. Today, as I understand it, it does.
Britain got some (but very little) news coverage a few years back, when it came to light that they had changed the categorization of certain crimes (such as home invasion robberies) to produce lower crime statistics.
People in the US do it, as well, "adjusting" their parameters so that the results produced are the ones desired, not the actual factual ones.
One of the big ones (I believe they were calling themselves "Handgun Control Inc." at the time, they have changed their name several times, since) got "busted" about their statistics when an insider revealed that every death where a firearm was involved (any firearm), and the person(s) killed were under 25 years old, was reported by them as "death of a child, due to a handgun".
If they use the argument that today's violence problems are due to the "easy availability" of guns, you might point out that 50 years ago, there were no background checks, (instant or otherwise), gun dealers were not required to have Federal licenses, convicted felons were not prohibited from having guns FOR LIFE (only while serving their sentences), guns could be bought through the mail, and delivered right to your door, and we didn't have the kind of problems then, that we do today.
Schools were not gun-free zones, indeed, some schools had rifle marksmanship teams and competitions. And, those "evil" military style weapons were available then, too. ARs and others. Guns were just as available back then, if not moreso than today. It is SOMETHING ELSE that has changed.
The way I see it, the something else that has changed is the reluctance to shoot other people, especially innocent people.