I think the laws of nature (or perhaps our definitions of mechanical things) would prevent using a cylinder as a shock absorber. I'm assuming the intent is to seal one end of the cylinder, and use it as a gas spring.
A shock absorber (in the normal automotive use of the term) is a damper, not a spring.
So you can't use a cylinder as a shock absorber unless you fill it with a liquid and have that liquid go through an orifice from one side of the piston, to the other.
I like Brandon's answer better though
