Many people point to "successful" gun bans in other countries, never noticing (or, at least never mentioning) how gun ownership was NOT a cultural norm in that country, and in many cases NEVER was.
Even England, the home and origin of many of our laws and cultural practices never had the wide spread common ownership of guns the US did, and mostly still does. And, the British have been reducing legal firearms ownership constantly and consistently for the majority of the past century.
The horrors of WW I so affected the British that during the 20s a very powerful movement against war, guns, and even anything even remotely martial grew to power and has been generally in control of policy there ever since. They managed so well that by 1940, with Nazi troops on the other side of the Channel, at looking like they were about to invade, England was begging for arms of any kind, from any source.
Their anti gun movement was smart enough to take a vacation when England was actually at war, and went right back to work as soon as the war was over.
Japan has essentially been as "gun free" as the rulers could make it since the time of the Shoguns.
There is no place on earth that ever had the cultural tradition of ordinary citizens legally owning guns that the US has. No other nation has that right boldly and bluntly stated in its founding documents the way the US does.
Of course their bans and restrictions are going to be successful (to a point, the criminal element doesn't care, and so, are never counted by those with the ban agenda), in places where people don't commonly own guns culturally.
A ban or restrictions on aluminum, siding, in a nation where the majority lives in grass or mud huts is going to be very "effective" as well. Likewise a law against eating pine cones in Fiji would be very "effective". If the people aren't doing it already, making it illegal usually works "effectively" to end or curtail the practice.
On the other hand, if its something the people are doing, and have been doing for generations, and something the people want to keep doing, making it against the law usually doesn't stop the practice (no matter what it is).
The only way the "whatever" that is newly banned gets stopped is by force, sometimes brutal force. Over enough time, constant enforcement can change the culture. This has been proven often enough in the real world.
The anti gunners know this, too.