Hi
Hi,
I recently bought a Diana G79 from a chap off this forum, it was in a bad way and I gave £37.50 for it for me to do up as a project. The 79 and the 80 are reasonably similar I believe. value of yours will depend on its condition.
The one I bought was not in the best condition, blueing on the metal was gone and the stock was scartched and nicked. I took the remaining blueing off the metal and have left it polished silver, the stock I stripped down, dyed and tru-oiled. I replaced the main spring with an Ox spring, the seals were ok when I got the rifle, PTFE breech seal and a rubber piston washer.
If you want replacement parts Chambers (which you mentioned) seems to be the best. Springs however you can get from most places, E*ay etc.
The stamped numbers by your trigger guard are the date the gun was made, which looks like 1980 to me.
Pics of mine after its refurb are on here: http://www.airgunbbs.com/forums/showthread.php?t=403382
After I had finished the gun was putting out 10ft/lb, was smooth and solid to shoot, good solid thunk, and was whisper quiet (the Logun silencer helps )
I like these guns and they are quite simple to work with, get stuck in!
B&C Weihrauch HW99s .22 3-9X40