If your document could potentially have tables with horizontally-merged cells, uneven cell widths in a column, or vertically-split cells, you need something like:
Code:
Sub TestTables()
Dim t As Long, c As Long, x As Long, y As Long, z As Long, StrTbls As String
With ActiveDocument
For t = 1 To .Tables.Count
With .Tables(t)
If .Uniform = True Then
z = .Columns.Count
If z = x Then StrTbls = StrTbls & ", " & t
If z > x Then x = z: StrTbls = t
Else
z = 0
With .Range
For c = 1 To .Cells.Count
y = .Cells(c).ColumnIndex
If y >= x Then z = y
Next
End With
If z = x Then StrTbls = StrTbls & ", " & t
If z > x Then x = z: StrTbls = t
End If
End With
Next
End With
MsgBox "The most columns (" & x & ") are found in table(s): " & StrTbls
End Sub