No so fast, bucko! Other countries have enacted strict gun regulations and have homicide rates well in excess of the United States. One of them is immediately to the south of the U.S.
In fact, according to the available data, the U.S. homicide rate is below the world average.
If strict gun laws actually made a difference, the effect should be more uniform.
Furthermore, the point is not to reduce gun homicides, it’s to reduce all homicides. You might want to check the British Home Office to see how that’s working out for them.
You don’t get to cherry-pick your comparisons when you are debating a person who knows better.