Rick Bressler said:

The Netherlands have a homicide rate about double that of the
English one, and only half as many guns…. So here we have The
Netherlands at about the lowest rate of gun ownership in Europe, and
the Swiss with one of the highest and the homicide rates are about
equal.

We really need to look at more data points….

I found ownership percentages for handguns in “Experiences of Crime across
the World” van Dijk, Mayhew and Killias (1991). These are from an
international victimization survey. (The survey asked about long guns too,
but the book does not report the answer.) I took the ownership percentages
for long guns from email from jgreely, who got them from an article by Don
Kates. I computed homicide rates from the World Health Organization
Statistical Yearbook, taking averages for 82-88 (except that values for
Belgium 85,87,88, Spain 87,88, USA 85 and NI 82 were missing). Result is
this table:

         Country  hom  hand   all
                  rate gun%  gun%
             USA  8.8    29  48.9
Northern Ireland  5.2   1.5
         Finland  2.9     7  25.5
          Canada  2.1     4  30.8
       Australia  2.0     2  20.1
        Scotland  1.8   0.5
         Belgium  1.8     6  16.8
     Switzerland  1.2    14  32.6
          Norway  1.2   3.5  31.2
          France  1.2   5.5  24.7
    West Germany  1.2   6.5   9.2
           Spain  1.0     2
     Netherlands  0.9     1   2.0
 England & Wales  0.7   0.5   4.7

(52% of the Swiss handguns were identified as army guns.)

There do seem to be moderate positive correlations between the
homicide rate, and gun ownership percentages.

For all guns the correlation coefficient was 0.71. Excluding the US gives a
correlation coefficient of 0.48.

For hand guns the correlation coefficient was 0.70. Excluding the US,
Switzerland, and NI (outliers) gives a correlation coefficient of 0.45.

(And of course, we know that correlation is not the same as causation.)