Well I don't really know why people think booleans are so hard to control.

Here is my test case, but I forgot to save the boolean parts before deleting history...



But that is okay because I then used google image to look at revolver cylinders and found that a lot of them have an indent in the sides so it gave me a chance to do an even more complex boolean. The whole operation took me about 5 minutes to set up, boolean, and clean up.



Booleans are not the evil that many would have you believe. You just have to think about what you are doing.

Even I goof up. After booleaning I realized I would have been better served to use a 12-side polygon for the outer cylinder since there are 6 holes and 6 indents. It was not hard to fix though as you can see at step 3 I just pulled the center vertices for the indented bits out using a 12-sided cylinder as my guide. (actually I just did 1 segment and then deleted everything else and made 5 copies rotating by 60 degrees for each copy). Even having to do all that, it still took me 5 minutes to complete the task.