retrieve the column letter for use in a formula

[grapevine]

I have been successfully using the following to retrieve the row number to use for formulas as in the following example

Dim rw As Long
rw = Range("a65536").End(xlUp).row
Range("R2:R" & rw).FormulaR1C1 = "=trim(rc[-17])"

but want to now retreive a column letter. I have adapted the following but when I hover my mouse over the line of code it is coming up with the number 13 rather than M

Dim cw As String
cw = Range("IV1").End(xlToLeft).Column
Range("A1:" & cw & "1").Select

In the last line of code if I replace the cw with the letter M in quotes the macro works so I think it must be how I have set the Dim statement, but I have tried different options but none seem to help as I keep getting runtime error 1004

I would be really grateful if someone could point out where I am going wrong

 

[niceguy_jay]

unfortunately the VBA code doesn't return the column letter but the column number...
thats why you are getting 7

use this code instead

Dim cw As Integer
cw = Range("IV1").End(xlToLeft).Column
ActiveSheet.Range(Cells(1, 1), Cells(1, cw)).Select

 

[grapevine]

Thank you so much, this works perfectly.
Your help is much appreciated.