SpudFiles

hey fellas. for my second gun i wanted to make it so i could get 2-3 shots out of 1 fill. but here is where my problem lies I don't want to have the old spring behind the piston. I would rather have the chamber with a b valve on it. Here is the design,
but i have a few questions, will the piston still seal against the barrel or does air still have to past by the piston? also is it possible for me to pilot the valve from where it is shown?
Sorry about all the questions. but this is the only question i couldn't find an answer to by searching.

You have you pilot valve where the chamber is supposed to be and the chamber where the pilot valve is supposed to be.

thats what i figured, but i still cant figure out how to seal the piston with the firing chamber? without creating a lot of dead space.