Funny you should ask.........I have one to do tomorrow! All parts are available.
You will find this inside http://i202.photobucket.com/albums/a...1/0006copy.jpg
And some parts may look like this too http://i202.photobucket.com/albums/a...1/0005copy.jpg.
The 75 is not a rifle for the faint hearted to tackle & you WILL need a spring compressor of some kind.
Make your own tools for removing the cog & cylinder end caps, don't try to use grips. If the seals are like those in the image above the cylinder end cap could be unbelievably difficult to get moving.
Oh I for got to mention, there are 3 breech seal sizes, 2.5.....3.0.....3.5mm thickness if you put one in that's too thick the rifle won't fire because the breech won't shut ( & this won't be as obvious as you may think) so it can't release one of the safe mecanisms