Copolymerizations of propene with norbornene were carried out using a syndiotactic metallocene catalyst at low initial comonomer concentrations for different polymerization times. The influence of the norbornene concentration on the catalytic activity and on the resulting material properties has been analyzed. The copolymer molecular weight decreased drastically when small amounts of norbornene were added in reactions which lasted 30min. When longer reaction times were used the molecular weight increased with time, however living polymerization was ruled out because the polydispersity was ca. 2. The DSC measurements showed copolymers with low crystallinity or which were completely amorphous.