Hey Dinny,
Here's a thought for you.
Why not use a concealed s/s rivet (or brass) and instead of tapping a hole in the hammer, just make a clearance hole for the threaded portion. Then you will have 7/8" extension and you can rough it up or wrap it with a grippy material. Just a thought, but it gets you much further past your scope bell possibly.
This is a link to the PDF version of Jantz Knifemaking supplier and is a little large:
http://www.jantzsupply.com/documents/newcatalog46final.pdfThis is a picture from page 33 of the stainless bolt, but there are also nickel silver and brass variants.
The only other thing you might do with it is replace the thick capscrew on the short side with a std. s/s head screw. I don't know how much weight will be, but I'm sure it'll be more than a std. one. heh What do you think?