I got my son the same rifle for Christmas about a year and a half ago. He would have been about 7 1/2 then.
They are great little rifles but I ran into the same problem you did. I ended up getting a piece of pipe insulation, cutting it in half and taping it on the stock with electrical tape as I couldn't find a lace up job that worked. He has just turned 9 and dosen't need the riser anymore.
Awesome pics and keep it up with the little guy!
