[holmux]

Would it be possible to buy a special screw driver to disassemble the cylinder on a Ruger gun, and does anyone know the size for this, or do I make one my self ?

It looks to me like I need a screwdriver that’s hollow, like as a small pipe, it would be possible to make one, but I would prefer to buy it of the shelve.

Any good advice ?

[dfariswheel]

Brownell's used to sell these specialty spanner wrenches for Ruger.
I'd email or call them.

If they no longer carry them, you can make a tool from a good grade of steel rod by drilling a hole in the middle and filing the end to form the lugs.
Harden and temper the tool and either mount it in a screwdriver handle, or drill a cross hole and install a "tee" handle.

[holmux]

I will give Brownell's a call

Thanks

[BSlacker]

Take a dremal like tool with a cutting wheel installed and an inexpensive straight screwdriver bit. Using the cutting wheel make a slot in the center of the bit wide enough to go over the center pin and deep enough to catch the slots in the little nut. Just takes a second and works great and you did it yourself. :)