during my trouble times, i was working on a modification for my TF 79. I had ordered a thumbhole stock, QB 79 parts ie. main tube and tank block.
the modification was to be able to run a 12 co2 tank instead of the 9 oz or air source tanks, and to use a full length shroud on the little lady.
the R&D went smooth and the machining went ok. The measurements I took did not match the main tube I was going to use, So the old saying to measure twice and cut once really means something. I have measured the main tube from a standard QB, a tech force 79 and the Qb-79 tube each one was different.
here's the pic of the riser I though of and made , it is sitting aobut 1/4 of ainch above the main tube.
Here's the picture of the gun with the 12oz c02 and full shroud

the guns is shooting gamo hunters @ 841 fps 13 fpe. The gun is shot all you hear is the hammer hitting the valve and the impact of the pellet.
Now if I can find someone to take this over and manufacture them, with my premission. I sure we can work something out
