Good to Know is a new feature that allows members of the community to answer questions from WebMD experts, doctors, staff, and other community members. We're testing this new feature and we'd like your feedback.
the cylinder (known as Bottom Dead Centre or BDC) the exhaust valve starts to open. As the piston now moves up the cylinder, the hot gases (consisting mostly of nitrogen, carbon dioxide, water vapour and unused oxygen) are expelled from the cylinder. As the Piston approaches TDC again the inlet valve starts to open and the cycle repeats itself.
I would agree. Physics would probably show that the amount of gas expelled through the gap between cylinder and barrel comes to a maximum after a certain barrel length (of course depending on powder and wideness of gap). From then on, the longer barrel would not lose any compression anymore, and therefore the velocity would once again go up.