Custom Crosman 2240

[clarky]

I know this is a foolish thought that will lead to money dissapearing faster than in a Polish Lap-Dancing bar, but I want to make a custom pistol and I think the Crosman 2240 is a good base to start from.
My objective is to make a full power pistol in as small a package as possible. I have done this with TAC, rim-fire and black powder in France, but now want one here where both the "fun" options are out.

My thought process so far is to shorten the barrel, which I've done before, but also the tube to use 8g co2 caps rather than the usual 12g. After that I would like to reduce the frame in the grip area to reduce height (so I expect custom grips will be needed) and fit a metal breech. I don't want to fit optics, rather make/fit low-profile, fixed open sights.
I want small and 5 ft/lb, I don't really care about shot count.

So, I expect there are many who have done this, pics, pointers and tips appreciated.

Tin ...if you your shortening your barrel but sticking on Co2 5ftlbs aint gonna happen.
Ive done a few and these figures may prove helpful for a .22 specimen only ..
Most dramatic velocity increase comes from a longer barrel, mainly required for when the weather gets cold like now and your gun dropping a full ftlb from a stocker barrel.
You can get 15 to 20 fps by using a fishtank airline gasket of silicone but ive used square section rubber washers to even better effect ....let me know if you want sizes...
If you machine off the probe section which contains porting and replace with a 2mm stainless steel probe 1.5 mm longer than stock, you will get 15 fos from increased flow and better seating of pellet past the transfer port. Tip of new probe is best with a 2 mm radius.
Flat topping the valve can create better flow for again 15 fps....
Chopping your barrel loses roughly 50 fps per 2 inches and increase that for cold condiitions...
Could keep standard cylinder and lose a bit of barrel to flush it to cylinder length. Above mods then restoring your 50 fps loses ....
Hammer spring increase will lose you shot count which does not worry you ....but this one gives 12 to 18 fos..
Use a deltin guide top hat for inside hammer spring with a 3 mm flange for a shade more pre load and removes the twang from the spring and makes it more efficient ...but gains are often smaller than written about on American websites..
10 to 15 fps at most.